[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
I agree that for web use Jpg may very well be a necessity and that sharpening just before converting to a given level of compression when converting to JPG may be the best way to go since in most case those downloading the web image will not be resizing the image for serious uses and/or then resaving that reworked image at a differetn level of compression as a new JPG file using the Save As function. For other than web work, some have suggested that saving an image for archival purposes as a LWZ compressed TIFF file is the best way to go for compression without artifacts. I, personally, use Genuine Fractals to produce a compressed working archival file in which I sharpen the image prior to encoding or leave it unsharpened until I open it up at the size that I need it to be. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Maris V. Lidaka Sr. Sent: Saturday, June 08, 2002 9:37 PM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: JPG sharpening [was: Color spaces for different purposes] True enough, but if the image requires sharpening? JPG is not a good format, I know, but it is very useful and in fact necessary for the web. I would think it better to convert to JPG and then sharpen rather than sharpen in TIFF and then convert. I haven't tested but I think it would result in fewer artifacts. Maris snip... Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Tony writes: This is only a minor sharpening to restore the sharpness of the original ... Sharpness cannot be restored, it can only be simulated. Sharpening causes deterioration in image quality, so it should be avoided until the image is about to be prepared for a specific use. I archive all my images without sharpening. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Laurie writes: Theoretically maybe ... All images are bitmaps at the time of sharpening. The format in which they were or will be stored is irrelevant. Additionally, all sharpening degrades an image, so it should not be carried out for images that are being archived, as you may need the highest possible image quality later on. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Ken writes: But when printing it's best to go direct from the TIFF isn't it? It doesn't matter. When producing for the web, yes, I go to jpeg and then sharpen. You can't. All images are bitmaps while you are manipulating them. JPEG and TIFF are just file formats. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Preston writes: One pre-press expert in my area recommends ColorMatchRGB instead of Adobe98 for pre-press work. Is this a Mac vs. PC thing? No, it is more of a printed-on-paper vs. electronic-display thing. ColorMatchRGB is designed for print, whereas Adobe98 is for more general use and has a gamut somewhat larger than what will usually fit on offset printing. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Ken writes: ... but could someone offer a technical explanation of why sharpening has so much more visible effect on jpegs as opposed to TIFFs? It doesn't. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Laurie writes: ... how does one sharpen between the conversion stage and the compression stage? One does not. There seems to be a widespread misconception here. While you are editing an image, it _does not have_ a format; it isn't JPEG, or TIFF, or anything else. The image is stored on a file in JPEG or TIFF or whatever format you choose, but it has no format during editing, and so whether you edit a file opened from TIFF or JPEG makes absolutely no difference while you are editing. An image in an editing program is just a mass of pixels. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Maris writes: Sharpening at that point was what I was suggesting, before saving as a more-compressed JPG. Sharpening permanently diminishes the quality of an image, and it also makes the resulting JPEG file somewhat larger. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Maris writes: True enough, but if the image requires sharpening? You cannot know if an image will require sharpening or not until you know how the image will actually be used. I would think it better to convert to JPG and then sharpen rather than sharpen in TIFF and then convert. Neither of these operations is possible. You cannot sharpen anything while it is stored in a TIFF or JPEG file; you must open the file, read the image data inside, and load it into an image-editing program such as Photoshop in order to sharpen it. While the image is in Photoshop, it _does not have_ a format; it is not TIFF or JPEG or anything else. When you store the image, it is recorded in a file in TIFF or JPEG format. But you cannot sharpen an image in TIFF or sharpen an image after conversion to JPEG; neither of these makes any real sense. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Laurie writes: For other than web work, some have suggested that saving an image for archival purposes as a LWZ compressed TIFF file is the best way to go for compression without artifacts. True--TIFF is lossless, and so it does not create artifacts. However, if you save an image as JPEG using the lowest (least) possible compression, the saved version will be essentially identical to the original scan. Scans do not contain more detail than a low-compression JPEG can hold. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Density vs Dynamic range
CCDs, in and of them selves, don't have anything to do with number of bits, as they are analog devices, but their dynamic range does... If the CCD has a dynamic range of 5000:1, it will require a 13 bit A/D to be able to extract the full dynamic range of the CCD. Regards, Austin Austin, I have kept out of this up to now, but I have step in to disagree with this as it's just plain wrong. The range of the CCD can be represented by any number of bits. What will vary is the degree of resolution of different values within the range. If all bits off represents total blackness and all bits on represents clear film (or no film) then the number of bits available defines the number of steps within the range. The more bits available the smaller the steps and the smoother the output. The dynamic range of the scanner is determined by how much noise is generated in the CCD. It's relatively easy (in electronic terms) to adjust the high point (all bits on) to be just at the clear film position, but all electronic devices generate noise and there is no point setting the bottom point deep in the noisy region. Some manufacturers do this which is why people complain of noisy shadows (slides) or skies (negatives). (There are techniques of using multiple scans to eliminate random noise, but they take time.) Peter, Nr Clonakilty, Co Cork, Ireland Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Anthony writes ... Laurie writes: ... how does one sharpen between the conversion stage and the compression stage? One does not. There seems to be a widespread misconception here. While you are editing an image, it _does not have_ a format; it isn't JPEG, or TIFF, or anything else. The image is stored on a file in JPEG or TIFF or whatever format you choose, but it has no format during editing, and so whether you edit a file opened from TIFF or JPEG makes absolutely no difference while you are editing. An image in an editing program is just a mass of pixels. I believe the misconception of always sharpening before JPEG comes from the common down-sampling. That is, most images start out big before being down-sized for wwweb presentation ... and the usual advice is: ... down-size ... sharpen (to remove the softening side-effects of down-sampling) ... and save as JPEG. cheerios ... shAf :o) Avalon Peninsula, Newfoundland www.micro-investigations.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Density vs Dynamic range
Peter, CCDs, in and of them selves, don't have anything to do with number of bits, as they are analog devices, but their dynamic range does... If the CCD has a dynamic range of 5000:1, it will require a 13 bit A/D to be able to extract the full dynamic range of the CCD. Regards, Austin Austin, I have kept out of this up to now, but I have step in to disagree with this as it's just plain wrong. Well, I know it's just plain right. And, funny enough YOU agree with what I said in your supposed disagreement! I don't mind a misunderstanding, or questioning what I wrote, but if you're going to blurt out that something is just plain wrong you ought to read carefully, and understand, what was said before saying that. I know exactly how these things work. I design with them for a living. Even most of the new CCD specs give a number of bits! Go read the Kodak spec for the Kli14403 sensor. It says Dynamic range - 12 bits and later goes on to say Dual mode operation is provided to increase dynamic range to 14 bits. They base this on the dynamic range which is based on noise...exactly what I said above. The range of the CCD can be represented by any number of bits. Yes it can (as I've said many times, if YOU read my posts), but that has nothing to do with what I said. READ IT AGAIN. To extract the FULL dynamic range... NOTE THE WORD FULL. There IS FOR A FACT an optimal number of bits, as I said, as Kodak also says. If you use less, you will NOT get the FULL dynamic range, and if you use more, you will not get any better data. What will vary is the degree of resolution of different values within the range. Yes, but it gets to a point where more bits does you NO good because you are simply reading noise. That is what limits dynamic range. The dynamic range of the scanner is determined by how much noise is generated in the CCD. Correct, and if you understood what I wrote, I said the EXACT same thing. I fail to see where I was just plain wrong as you say the EXACT same thing I said. Plain and simple, do you agree that a dynamic range of 5000:1 REQUIRES 13 bits to represent every integer value between 1 and 5000? If so, then where's the problem? If not, then plain and simple, why not? Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Onboard Graphics and Filmscanning
A friend with a Coolscan IV and a very slow PC wants a faster PC. For a similar price I can build at fast 1700 Athlon, 512 meg RAM with a separate 32 Meg video card PC or he can purchase a similar spec machine ready built with onboard video that shares the system RAM. The cost of machines ready built with a separate card is considerably dearer. Has any one edited say 30 Meg scans with a machine with onboard video,. My thoughts are it will be noticeably slower than a machine with a separate 32 meg video card. If not, it saves me building him a machine. Comments please. Eddie Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
I support Ken. I'm currently scanning a large number of rolls of negative film. They are just 10x.6.67 inch by 72 ppi images for screen display. I'm keeping them in an electronic catalog of my images. Unless something has changed in Photo Shop 7, which I recently acquired, sharpening is much more noticeable on these small JPEGs than on 27MB TIFFs that I use for printing or creating slides. I would like to emphasize the word visible in Ken's question. Don At 10:22 AM 09/06/2002 +0200, you wrote: Ken writes: ... but could someone offer a technical explanation of why sharpening has so much more visible effect on jpegs as opposed to TIFFs? It doesn't. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Tomek Zakrzewski [EMAIL PROTECTED] asked: What color spaces is best to choose for the following purposes: - printed material, for example a magazine or a photographic book - stock photography (image bank) - inkjet and Maris V. Lidaka Sr. [EMAIL PROTECTED] suggested: I also would suggest Adobe RGB. I would not sharpen the images yet - sharpen when you are ready to print on inkjet or to send to the publisher, as your sharpening amount will probably be different. Some publishers will do the sharpening themselves AFAIK. --- Maris has excellent advice. For a fuller story, try a Googlesearch for: (color space RGB colormatch sRGB Adobe) and you will get lot's of informative links. One pre-press expert in my area recommends ColorMatchRGB instead of Adobe98 for pre-press work. Is this a Mac vs. PC thing? Preston Earle [EMAIL PROTECTED] I was at a recent event with industry experts and one gentleman who is highly respected in the area uses Colormatch RGB because of the large number of files created in Photoshop 4.0. Also, if a file is given to a non-color managed company, the Colormatch RGB image will survive a stripped out profile better in general because it closely resembles the Mac monitor space. The sacrifice is that bright blues and greens will be sacrificed a bit., which probably doesn't matter for offset printing, but might matter when outputting to a Lightjet or other continuous tone process. All the best! -Andrew Darlow Photography, Digital Print Consulting and Custom Editions Andrew Darlow Images International, NYC - www.andydarlow.com Author: Inkjet Tip of the Month Club (newsletter) To subscribe, send e-mail to: [EMAIL PROTECTED] -- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Good point - you are correct. Maris - Original Message - From: Anthony Atkielski [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 3:33 AM Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for different purposes] Maris writes: True enough, but if the image requires sharpening? You cannot know if an image will require sharpening or not until you know how the image will actually be used. I would think it better to convert to JPG and then sharpen rather than sharpen in TIFF and then convert. Neither of these operations is possible. You cannot sharpen anything while it is stored in a TIFF or JPEG file; you must open the file, read the image data inside, and load it into an image-editing program such as Photoshop in order to sharpen it. While the image is in Photoshop, it _does not have_ a format; it is not TIFF or JPEG or anything else. When you store the image, it is recorded in a file in TIFF or JPEG format. But you cannot sharpen an image in TIFF or sharpen an image after conversion to JPEG; neither of these makes any real sense. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Onboard Graphics and Filmscanning
I use an onboard video card (8MB?) in an 800MHz Pentium 3, 512MB RAM PC. I can't compare speeds to a 32MB video card but the speed of my editing is fine. Maybe I don't appreciate the speed of a 32MB video card but I can't imagine a huge difference when I manipulating 27MB (8 bit) or 55MB (16 bit) images. Changes in PS7 are very quick, a fraction of a second usually. Scanning is a different story but that has nothing to do with the video card. Don At 03:08 PM 09/06/2002 +0100, you wrote: A friend with a Coolscan IV and a very slow PC wants a faster PC. For a similar price I can build at fast 1700 Athlon, 512 meg RAM with a separate 32 Meg video card PC or he can purchase a similar spec machine ready built with onboard video that shares the system RAM. The cost of machines ready built with a separate card is considerably dearer. Has any one edited say 30 Meg scans with a machine with onboard video,. My thoughts are it will be noticeably slower than a machine with a separate 32 meg video card. If not, it saves me building him a machine. Comments please. Eddie Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] SS4000 scans--strange pixel spike in histogram
I ran this question by last week and received one reply that wasn't the solution. Some of my recent scans done on an SS4000 are showing an odd spike in the histograms. I first noticed this when I was doing Levels correction in Photoshop. I checked the histograms in both Polacolor Insight and VueScan as I did more scans and noticed the same thing. Here is an example of what I mean: http://www.tallgrassimages.com/test/histogram.jpg These single level pixel spikes seem to be in the blue channel. I can't see any streaking or lines or other anomalies on the scanned images themselves. Sometimes there will be a very high pixel count in the spike as reported by Photoshop. Sometimes the spike is visible but Photoshop doesn't register a high pixel count at that particular level. These spikes seem to occur most commonly at level 0 or level 1. They are not the same from slide to slide and some slide scans don't produce such a spike. Any ideas? Stan Schwartz [EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
On Sun, 9 Jun 2002 10:52:22 -0230, you wrote: There seems to be a widespread misconception here. While you are editing an image, it _does not have_ a format; it isn't JPEG, or TIFF, or anything else. The image is stored on a file in JPEG or TIFF or whatever format you choose, but it has no format during editing, and so whether you edit a file opened from TIFF or JPEG makes absolutely no difference while you are editing. An image in an editing program is just a mass of pixels. I believe the misconception of always sharpening before JPEG comes from the common down-sampling. That is, most images start out big before being down-sized for wwweb presentation ... and the usual advice is: ... down-size ... sharpen (to remove the softening side-effects of down-sampling) ... and save as JPEG. \ OK, I think I'm getting clear here. So let me rephrase a bit. When I scan an image - into whatever file formet, I use TIFF out of Vuescan - and then open it in PS, I can immediately see some sharpness loss which I understand to be a result of the scan - scanner limitation, etc. One eventual step in my workflow is usually to try to restore the image to something resembling the original slide, through the use of as little sharpening or USM as possible. If I try that on my original file - before down-sampling - I have to use large USM values to see any effect at all, or use sharpen more (I'm using PS Elements at the moment). Once I've resized for the web - typically to 800 pixels in long dimension, which I do using a bicubic resample and changing the resolution, usually to about 600dpi from 2720 - the file shrinks from its former +/-20MB to about 1.25MB and sharpening must be done very cautiously in order to avoid halos and other artifacts. When I resize for *print* I don't resample, I just change the dimensions and leave the resolution the same. It's in the down-sized scan that I see the change in sharpening response. So, aside of asking for any observation regarding improving my workflow - why is the sharpening so much more effective on the smaller image? And am I losing something I'm not yet aware of?I'm sure a much more experienced eye can detect sharpening artifacts in my stuff, but I've been relatively pleased with the results. 2 examples - feel free to criticize: http://www.photosig.com/viewphoto.php?id=716 http://www.photosig.com/viewphoto.php?id=29447 But I'd like to understand more and get better results. Thanks for all the explanations! Ken Durling Visit my new easier-to-browse PhotoSIG portfolio: http://www.photosig.com/viewuser.php?id=203 Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
-Original Message- So, aside of asking for any observation regarding improving my workflow - why is the sharpening so much more effective on the smaller image? In PS there are three parameters for USM. One of them is the radius. The bigger the radius the more surounding pixels are taken into account for sharpening. Now if you downsample your image it is kind of like compressing mutliple pixels into one pixel. For USM that has the same effect as increasing the radius. Therefore, if you use the same radius for the original image and the downsampled image then the effect of sharpening will be stronger for the downsampled image. Maybe this is what you see. Make sure you also play with the other two parameters. Robert Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
So the moral of the story is you have to know your printing company and act accordingly. Perhaps save in Adobe RGB for now, and when you find a printer talk to them - you can then convert to Colormatch RGB if they are not color-management aware or if that's what they prefer. Maris - Original Message - From: Andrew Darlow [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 9:55 AM Subject: [filmscanners] Re: Color spaces for different purposes Tomek Zakrzewski [EMAIL PROTECTED] asked: What color spaces is best to choose for the following purposes: - printed material, for example a magazine or a photographic book - stock photography (image bank) - inkjet and Maris V. Lidaka Sr. [EMAIL PROTECTED] suggested: I also would suggest Adobe RGB. I would not sharpen the images yet - sharpen when you are ready to print on inkjet or to send to the publisher, as your sharpening amount will probably be different. Some publishers will do the sharpening themselves AFAIK. --- Maris has excellent advice. For a fuller story, try a Googlesearch for: (color space RGB colormatch sRGB Adobe) and you will get lot's of informative links. One pre-press expert in my area recommends ColorMatchRGB instead of Adobe98 for pre-press work. Is this a Mac vs. PC thing? Preston Earle [EMAIL PROTECTED] I was at a recent event with industry experts and one gentleman who is highly respected in the area uses Colormatch RGB because of the large number of files created in Photoshop 4.0. Also, if a file is given to a non-color managed company, the Colormatch RGB image will survive a stripped out profile better in general because it closely resembles the Mac monitor space. The sacrifice is that bright blues and greens will be sacrificed a bit., which probably doesn't matter for offset printing, but might matter when outputting to a Lightjet or other continuous tone process. All the best! -Andrew Darlow Photography, Digital Print Consulting and Custom Editions Andrew Darlow Images International, NYC - www.andydarlow.com Author: Inkjet Tip of the Month Club (newsletter) To subscribe, send e-mail to: [EMAIL PROTECTED] -- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Initial sharpening is what Bruce Frasier recommends: http://www.creativepro.com/story/feature/12189.html As to the effectiveness of sharpening on the smaller image - you have fewer pixels to work with, so the same sharpening radius will be much more visible. Maris - Original Message - From: Ken Durling [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 10:43 AM Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for different purposes] [snipped] OK, I think I'm getting clear here. So let me rephrase a bit. When I scan an image - into whatever file formet, I use TIFF out of Vuescan - and then open it in PS, I can immediately see some sharpness loss which I understand to be a result of the scan - scanner limitation, etc. One eventual step in my workflow is usually to try to restore the image to something resembling the original slide, through the use of as little sharpening or USM as possible. If I try that on my original file - before down-sampling - I have to use large USM values to see any effect at all, or use sharpen more (I'm using PS Elements at the moment). Once I've resized for the web - typically to 800 pixels in long dimension, which I do using a bicubic resample and changing the resolution, usually to about 600dpi from 2720 - the file shrinks from its former +/-20MB to about 1.25MB and sharpening must be done very cautiously in order to avoid halos and other artifacts. When I resize for *print* I don't resample, I just change the dimensions and leave the resolution the same. It's in the down-sized scan that I see the change in sharpening response. So, aside of asking for any observation regarding improving my workflow - why is the sharpening so much more effective on the smaller image? And am I losing something I'm not yet aware of?I'm sure a much more experienced eye can detect sharpening artifacts in my stuff, but I've been relatively pleased with the results. 2 examples - feel free to criticize: http://www.photosig.com/viewphoto.php?id=716 http://www.photosig.com/viewphoto.php?id=29447 But I'd like to understand more and get better results. Thanks for all the explanations! Ken Durling Visit my new easier-to-browse PhotoSIG portfolio: http://www.photosig.com/viewuser.php?id=203 Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Density vs Dynamic range
Plain and simple, do you agree that a dynamic range of 5000:1 REQUIRES 13 bits to represent every integer value between 1 and 5000? If so, then where's the problem? If not, then plain and simple, why not? Austin I think where we differ is the assumption the a 5000:1 dynamic range yields 5000 discrete integer values. Light intensity is a linear value so that 5000:1 range can be divided into as many steps as you'd like to use. It is in any case only a ratio and therefore has no units or integer values. If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. If the CCD has an integrated A to D and thus the number of output bits is fixed, then I'd agree with your statement. If not, then your statement is still wrong, or at best, an over-simplification. I've followed this discussion with some interest and realise that many people are confusing number of bits (i.e. the number of discrete values that can be represented) with the dynamic range of the CCD which could with the right A to D behind it, provide as many bits as required. I'm sure you'll agree that it's the noise floor and the saturation level that define the true dynamic range. Peter Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Archiving and when to sharpen (was: Color spaces for differentpurposes)
Sharpness cannot be restored, it can only be simulated. Sharpening causes deterioration in image quality, so it should be avoided until the image is about to be prepared for a specific use. I archive all my images without sharpening. Agree. This is how I do mine. I'll do all the crop, tonal and other adjustments -- except resizing -- and archive that photoshop psd file (and the original vuescan raw scan file). Then for specific purposing I'll resize or resample as appropriate and sharpen as a last step before sending file to its destination. As this discussion has pointed out, the specific actions for purposing will be different depending on the use and destination. Even sharpening: some places will do their own sharpening (as mentioned). If I know this then I'll only lightly sharpen edges (a first stage of a two pass sharpening process, described in a Creativepro article by Bruce Fraser at www.creativepro.com/story/feature/12189.html?origin=story). This article addresses one of the discussion items of this thread here: in Fraser's words one of the important questions about sharpening: When in the image-editing process should you sharpen? Another aspect of purposing, different for different destinations, is the file format. I've had more than one publicist and publisher request that I provide (email, ftp) a jpeg in preference to a tiff because of the file size. (For this I use a high/maximum quality in photoshop terms: 10 to 12.) -- Bob Shomler http://www.shomler.com/ Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen (was: Color spaces for differentpurposes)
Another aspect of purposing, different for different destinations, is the file format. I've had more than one publicist and publisher request that I provide (email, ftp) a jpeg in preference to a tiff because of the file size. (For this I use a high/maximum quality in photoshop terms: 10 to 12.) Although I concur with all you have said, I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit, lack of knowledgabout the ability to compress TIFFs using the lwz compression which is as good if not better than the JPG compression at levels 10-12, or a lack of any real concern over quality of the file they are getting. While jpg is the most known and common compression format on and for the web and may even be necessary if you are sending the file as an email attachment, to achieve that usefulness on the web or as an email attchment it is often necessary to use compression levels of 5 or less which really tends to loss a lot of data and information. However, for FTPing, it usually is not a necessity to reduce the file sizes to very small levels since most of the publishers and publicists generally have some sort of direct high speed connection to the internet and relatively large server space to store downloading files, as well as a desire to get maximum quality files. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Bob Shomler Sent: Sunday, June 09, 2002 12:28 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Archiving and when to sharpen (was: Color spaces for differentpurposes) Sharpness cannot be restored, it can only be simulated. Sharpening causes deterioration in image quality, so it should be avoided until the image is about to be prepared for a specific use. I archive all my images without sharpening. Agree. This is how I do mine. I'll do all the crop, tonal and other adjustments -- except resizing -- and archive that photoshop psd file (and the original vuescan raw scan file). Then for specific purposing I'll resize or resample as appropriate and sharpen as a last step before sending file to its destination. As this discussion has pointed out, the specific actions for purposing will be different depending on the use and destination. Even sharpening: some places will do their own sharpening (as mentioned). If I know this then I'll only lightly sharpen edges (a first stage of a two pass sharpening process, described in a Creativepro article by Bruce Fraser at www.creativepro.com/story/feature/12189.html?origin=story). This article addresses one of the discussion items of this thread here: in Fraser's words one of the important questions about sharpening: When in the image-editing process should you sharpen? Another aspect of purposing, different for different destinations, is the file format. I've had more than one publicist and publisher request that I provide (email, ftp) a jpeg in preference to a tiff because of the file size. (For this I use a high/maximum quality in photoshop terms: 10 to 12.) -- Bob Shomler http://www.shomler.com/ Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Density vs Dynamic range
Peter, It must be the nature of the discussion or the topic; but just when I think I am beginning to get a handle on it something muddies the water. :-) The first point of confusion in your discussion with Austin appears to be that what you are referring to as dynamic range he is referring to as density range or that you are using the two terms synonomously while he is using them as naming two different concepts. For instance, if I may take the liberty to put words in his mouth, take the statement: If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. I think apart from maybe disagreeing with the value coming from the CCD, he would say that what you are saying should read: If we double the number of bits (possible values) that doesn't increase the DENSITY RANGE of the scanner, only it's ability to represent accurately the DYNAMIC RANGE value CAPTURED AND DIGITALIZED by the scanner's analog to digital converter. (Austin, if you are reading this and I am putting the wrong spin on it or words in your mouth, please feel free to correct me.) I believe that he also might agree with your statements below if you changed dynamic range to density range and CCD to A/D converter. I've followed this discussion with some interest and realise that many people are confusing number of bits (i.e. the number of discrete values that can be represented) with the dynamic range of the CCD which could with the right A to D behind it, provide as many bits as required. Please take my comments as an exercise in clarification for my own benefits and not as a criticism or assertion that mu understandings are truth. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 12:05 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Density vs Dynamic range Plain and simple, do you agree that a dynamic range of 5000:1 REQUIRES 13 bits to represent every integer value between 1 and 5000? If so, then where's the problem? If not, then plain and simple, why not? Austin I think where we differ is the assumption the a 5000:1 dynamic range yields 5000 discrete integer values. Light intensity is a linear value so that 5000:1 range can be divided into as many steps as you'd like to use. It is in any case only a ratio and therefore has no units or integer values. If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. If the CCD has an integrated A to D and thus the number of output bits is fixed, then I'd agree with your statement. If not, then your statement is still wrong, or at best, an over-simplification. I've followed this discussion with some interest and realise that many people are confusing number of bits (i.e. the number of discrete values that can be represented) with the dynamic range of the CCD which could with the right A to D behind it, provide as many bits as required. I'm sure you'll agree that it's the noise floor and the saturation level that define the true dynamic range. Peter Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
Really good answer Robert. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Robert Meier Sent: Sunday, June 09, 2002 11:27 AM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: JPG sharpening [was: Color spaces for different purposes] -Original Message- So, aside of asking for any observation regarding improving my workflow - why is the sharpening so much more effective on the smaller image? In PS there are three parameters for USM. One of them is the radius. The bigger the radius the more surounding pixels are taken into account for sharpening. Now if you downsample your image it is kind of like compressing mutliple pixels into one pixel. For USM that has the same effect as increasing the radius. Therefore, if you use the same radius for the original image and the downsampled image then the effect of sharpening will be stronger for the downsampled image. Maybe this is what you see. Make sure you also play with the other two parameters. Robert Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was: Color spaces fordifferent purposes)
I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit ... From one, file size was specifically mentioned. Others may be due to habit, or their experience that once image goes through their prepress and screening they likely cannot discern a difference in the printed result. Bob Shomler Another aspect of purposing, different for different destinations, is the file format. I've had more than one publicist and publisher request that I provide (email, ftp) a jpeg in preference to a tiff because of the file size. (For this I use a high/maximum quality in photoshop terms: 10 to 12.) Although I concur with all you have said, I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit, lack of knowledgabout the ability to compress TIFFs using the lwz compression which is as good if not better than the JPG compression at levels 10-12, or a lack of any real concern over quality of the file they are getting. While jpg is the most known and common compression format on and for the web and may even be necessary if you are sending the file as an email attachment, to achieve that usefulness on the web or as an email attchment it is often necessary to use compression levels of 5 or less which really tends to loss a lot of data and information. However, for FTPing, it usually is not a necessity to reduce the file sizes to very small levels since most of the publishers and publicists generally have some sort of direct high speed connection to the internet and relatively large server space to store downloading files, as well as a desire to get maximum quality files. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Color spaces for different purposes
Of course, I hope you understand that my question was rhetorical. I hope that you were just using my rhetorical question as a vehicle for expressing your remarks rather than taking it seriously as a literal question in need of an answer. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Sunday, June 09, 2002 3:29 AM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Color spaces for different purposes Laurie writes: ... how does one sharpen between the conversion stage and the compression stage? One does not. There seems to be a widespread misconception here. While you are editing an image, it _does not have_ a format; it isn't JPEG, or TIFF, or anything else. The image is stored on a file in JPEG or TIFF or whatever format you choose, but it has no format during editing, and so whether you edit a file opened from TIFF or JPEG makes absolutely no difference while you are editing. An image in an editing program is just a mass of pixels. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: SS4000 scans--strange pixel spike in histogram
I have not noticed this with my SS4000. Can you scan the same slides on another scanner (not necessarily another SS4000 although that would be good) to see if it's an anomaly with your scanner? Tom -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of S Schwartz Sent: Sunday, June 09, 2002 11:16 AM To: [EMAIL PROTECTED] Subject: [filmscanners] SS4000 scans--strange pixel spike in histogram I ran this question by last week and received one reply that wasn't the solution. Some of my recent scans done on an SS4000 are showing an odd spike in the histograms. I first noticed this when I was doing Levels correction in Photoshop. I checked the histograms in both Polacolor Insight and VueScan as I did more scans and noticed the same thing. Here is an example of what I mean: http://www.tallgrassimages.com/test/histogram.jpg These single level pixel spikes seem to be in the blue channel. I can't see any streaking or lines or other anomalies on the scanned images themselves. Sometimes there will be a very high pixel count in the spike as reported by Photoshop. Sometimes the spike is visible but Photoshop doesn't register a high pixel count at that particular level. These spikes seem to occur most commonly at level 0 or level 1. They are not the same from slide to slide and some slide scans don't produce such a spike. Any ideas? Stan Schwartz [EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
However, if you save an image as JPEG using the lowest (least) possible compression, the saved version will be essentially identical to the original scan. I agree with this; but in many if not most cases, the compression level used or required is greater then the lowest possible amount, ranging from level 6 to level 3 in order to get the file small enough to be an email attachment or a web site download. Scans do not contain more detail than a low-compression JPEG can hold. This statement I do not understand; please elaborate. Surely, this cannot be the case if we are talking about raw data as opposed to encoded compressed data even at the lowest setting in which there still is some compression of the raw data. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Sunday, June 09, 2002 3:36 AM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for different purposes] Laurie writes: For other than web work, some have suggested that saving an image for archival purposes as a LWZ compressed TIFF file is the best way to go for compression without artifacts. True--TIFF is lossless, and so it does not create artifacts. However, if you save an image as JPEG using the lowest (least) possible compression, the saved version will be essentially identical to the original scan. Scans do not contain more detail than a low-compression JPEG can hold. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: Although I concur with all you have said, I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit, lack of knowledgabout the ability to compress TIFFs using the lwz compression which is as good if not better than the JPG compression at levels 10-12, or a lack of any real concern over quality of the file they are getting. Hi Laurie, Is it not lzw compression instead of lwz? In any case, does the amount of reduction in the file size using lzw compression vary considerably with the content? The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Your comment that lzw compressed TIFF files are as small as JPGs made me wonder if you are working with graphic files and if they offer better compression than photos. Later, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Color spaces for different purposes
All images are bitmaps at the time of sharpening. The format in which they were or will be stored is irrelevant I have no problem with that. My reference was to the possibilities of separating the conversion process from the compression process when saving to JPG format and not with the state of the image at the time of sharpening. In practice, I do not think they are seperable so as to allow some other action to be carried out between the two processes, although it may be theoretically possible. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Sunday, June 09, 2002 3:24 AM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Color spaces for different purposes Laurie writes: Theoretically maybe ... All images are bitmaps at the time of sharpening. The format in which they were or will be stored is irrelevant. Additionally, all sharpening degrades an image, so it should not be carried out for images that are being archived, as you may need the highest possible image quality later on. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re:Polaroid sprintscan 4000 problems
I have tried the software (Insight) on another machine, with the same scanner, and SCSI card, and the instability is still there. Brian Boggenpoel On Sat, 8 Jun 2002 23:35:01 +0100 Eddie Cairns [EMAIL PROTECTED] Wrote: This could point to a PC hardware problem. Can you load the software on an other PC and check if that is also unstable when using the scanner. Sometimes RAM and Motherboard problems just happen at the worst of times. You have loaded the latest video drivers available I assume. Eddie Topic: Polaroid sprintscan 4000 problems Date: Sat, 08 Jun 2002 21:43:35 + From: brian boggenpoel I am using windows 98, firmware 1.4, which I downloaded about 3 weeks ago, pointing the temp files to a second hard drive with many Gb of space. I am using a stand alone version. Insight 5.5 would not start at all. I have been struggling with this for some time, and on the suspicion that there might be some conflicting software I have just reformatted the c: drive, (after getting very marginal improvements with lesser steps) and currently only have AOL and insight loaded on the machine. Unfortunately it is still very unstable. I will now try a completely install of Insight 5.5 Many thanks, Brian Boggenpoel. _ Chat with friends online, try MSN Messenger: http://messenger.msn.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Onboard Graphics and Filmscanning
Date sent: Sun, 09 Jun 2002 08:54:14 -0600 Send reply to: [EMAIL PROTECTED] From: Don Marcotte [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject:[filmscanners] Re: Onboard Graphics and Filmscanning I use an onboard video card (8MB?) in an 800MHz Pentium 3, 512MB RAM PC. I can't compare speeds to a 32MB video card but the speed of my editing is fine. Maybe I don't appreciate the speed of a 32MB video card but I can't imagine a huge difference when I manipulating 27MB (8 bit) or 55MB (16 bit) images. Changes in PS7 are very quick, a fraction of a second usually. Scanning is a different story but that has nothing to do with the video card. Don I also have onboard video, Intel mobo, PIII/800, 512MB RAM. I run 19 monitor at 1024x768 in 24bit (TrueColor) mode. No probs, plenty fast for PhotoShop. If you do 3D, especially gaming, this would NOT be adequate however.. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: SS4000 scans--strange pixel spike in histogram
My scanner is the only one I have access to. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Thomas B. Maugham Sent: Sunday, June 09, 2002 2:03 PM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: SS4000 scans--strange pixel spike in histogram I have not noticed this with my SS4000. Can you scan the same slides on another scanner (not necessarily another SS4000 although that would be good) to see if it's an anomaly with your scanner? Tom -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of S Schwartz Sent: Sunday, June 09, 2002 11:16 AM To: [EMAIL PROTECTED] Subject: [filmscanners] SS4000 scans--strange pixel spike in histogram I ran this question by last week and received one reply that wasn't the solution. Some of my recent scans done on an SS4000 are showing an odd spike in the histograms. I first noticed this when I was doing Levels correction in Photoshop. I checked the histograms in both Polacolor Insight and VueScan as I did more scans and noticed the same thing. Here is an example of what I mean: http://www.tallgrassimages.com/test/histogram.jpg These single level pixel spikes seem to be in the blue channel. I can't see any streaking or lines or other anomalies on the scanned images themselves. Sometimes there will be a very high pixel count in the spike as reported by Photoshop. Sometimes the spike is visible but Photoshop doesn't register a high pixel count at that particular level. These spikes seem to occur most commonly at level 0 or level 1. They are not the same from slide to slide and some slide scans don't produce such a spike. Any ideas? Stan Schwartz [EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Re:Polaroid sprintscan 4000 problems
For what it's worth, I had terrible instability with Polacolor and Win98. That problem completely disappeared with a switch to Win2000 Professional. Stan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of brian boggenpoel Sent: Sunday, June 09, 2002 3:23 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re:Polaroid sprintscan 4000 problems I have tried the software (Insight) on another machine, with the same scanner, and SCSI card, and the instability is still there. Brian Boggenpoel or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
Date sent: Sun, 09 Jun 2002 15:09:58 -0400 Send reply to: [EMAIL PROTECTED] From: Johnny Johnson [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject:[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: Although I concur with all you have said, I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit, lack of knowledgabout the ability to compress TIFFs using the lwz compression which is as good if not better than the JPG compression at levels 10-12, or a lack of any real concern over quality of the file they are getting. Hi Laurie, Is it not lzw compression instead of lwz? yes In any case, does the amount of reduction in the file size using lzw compression vary considerably with the content? yes; if there are many pixels of same color, image will compress more. The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes)
At 05:32 PM 6/9/02 -0400, Mac wrote: Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Hi Mac, Thanks for asking - it looks like the original TIFF file that I grabbed must have already been saved with lwz compression. So, I did the experiment again using a fresh scan of a different slide with the following results: TIFF: 56,264 kb TIFF with lzw compression: 35,364 kb JPG with Photoshop level 12:18,453 kb So, in both this case and the previous one, the JPG with level 12 compression is ~ 1/2 the size of a TIFF with lzw compression. Thanks again for bringing my mistake to my attention, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
It's not that unusual, though I don't recall why, and LZW compression will not reduce file size nearly as much as JPG Maris - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 4:32 PM Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) [snipped] The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Sharpening and JPEG/TIFF (was: Color spaces for different purposes)
Don, your support of Ken is a bit misplaced. TIFF vs. JPEG is non sequitur, Anthony is correct. This is about the pixels in the image, not about the file format in which it's saved. When an unsharp mask (a.k.a. sharpening) is applied to an image, it is enhancing the contrast of edges or areas of rapid level transition by lightening the light side, and darkening the dark side. This is done to the actual pixels in an image, independent of the image size resolution setting. The software analyzes the image and applies the sharpening effect within a certain pixel distance; this is the Radius setting in Photoshop's Unsharp mask, a typical distance could be e.g. 0.7 pixels. If you open your 27 MB file and the low res catalog scan, then apply the same unsharp mask to both, the edges enhancement is applied to the same distance in pixels around that edge in the image. These pixels, however, represent quite different distance in the image. If you view both at 100% resolution, and both happened to have a narrow feature 3 pixels wide in both, they both would be appear sharpened exactly the same. Now, naturally, a feature 3 pixels wide in the low-res image would be something close to 15 pixels wide in the high-res image. Therefore the edge-enhancing effect would appear much more pronounced on the low-res one. If you compared them side-by-side, your catalog scan might be all visible in the window when viewed at 100%; while the high-res would have to be zoomed out to 20% of actual, and the sharpening effect would be miniaturized on screen and be far less noticable. This is why you should never apply the unsharp masking on your high-res scans until the final target use of the image is known, and, if necessary, the image is resampled down for that use. For example, if you print a 360dpi image on a high quality inkjet printer on glossy media, you would need just a little unsharp masking, whereas printing the same image on offset press where the 4-color process screening will make images appear much softer you would need to apply a much stronger unsharp mask for the same final apparent crispness. If this same image was used for web, you would first downsample it to 72dpi, then unsharp mask it for appropriate level of crispness at that resolution. Sami Ken wrote: ... but could someone offer a technical explanation of why sharpening has so much more visible effect on jpegs as opposed to TIFFs? At 10:22 AM 09/06/2002 +0200, Anthony wrote: It doesn't. On Sunday, June 9, 2002, at 07:46 AM, Don Marcotte wrote: I support Ken. I'm currently scanning a large number of rolls of negative film. They are just 10x.6.67 inch by 72 ppi images for screen display. I'm keeping them in an electronic catalog of my images. Unless something has changed in Photo Shop 7, which I recently acquired, sharpening is much more noticeable on these small JPEGs than on 27MB TIFFs that I use for printing or creating slides. I would like to emphasize the word visible in Ken's question. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Laurie Solomon [EMAIL PROTECTED] asked: Scans do not contain more detail than a low-compression JPEG can hold. This statement I do not understand; please elaborate. Surely, this cannot be the case if we are talking about raw data as opposed to encoded compressed data even at the lowest setting in which there still is some compression of the raw data. The raw data is not truly random data. It is actually smoothly changing nearly continuous data. So there is a lot of room for lossless compression. Low-compression JPEG is very close to lossless compression, and only loses information in areas of high detail and contrast. Since raw scan data doesn't have such areas, JPEG works well. David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
Laurie writes: I agree with this; but in many if not most cases, the compression level used or required is greater then the lowest possible amount, ranging from level 6 to level 3 in order to get the file small enough to be an email attachment or a web site download. I was thinking only of archived photos. For Web and e-mail use, in most cases you can crank the compression all the way up in Photoshop (that is, set it down to 1, the highest compression setting) and the image will still look fine. Unlike some editing programs, Photoshop won't let you compress the image so much that it really looks bad on the screen; even the worst setting is still pretty good. This statement I do not understand; please elaborate. Most scans, at full resolution, do not actually hold enough detail to make full use of that resolution, so compressing them into JPEGs really doesn't sacrifice anything. Additionally, with the lowest compression settings of Photoshop (level 10), I have yet to be able to distinguish between the original and the JPEG in terms of image detail, even when greatly magnifying the image. Photoshop is very conservative. Surely, this cannot be the case if we are talking about raw data as opposed to encoded compressed data even at the lowest setting in which there still is some compression of the raw data. There is always some loss in a mathematical sense and a strict sense, but in practice you won't be able to see the loss when storing full-resolution scans as JPEGs with the quality setting set as high as it will go. I've never had any problem losing detail in archived JPEGs as long as I use the highest quality setting. I sure would like to see a 16-bit version of the JPEG standard, though. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Color spaces for different purposes
Laurie writes: In practice, I do not think they are seperable so as to allow some other action to be carried out between the two processes, although it may be theoretically possible. JPEG encoding requires the rough equivalent of a Fourier transformation on the data; once that is undertaking, bitmapped operations on the image are no longer possible. So one cannot really separate them. Not all encoding formats impose this constraint, but I haven't heard of any software that separates the two processes, just the same. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
yes; if there are many pixels of same color, image will compress more. And that is almost never true for real-world photographs, although it is certainly true quite often for computer-generated images such as diagrams and the like. Wow, are you sure? The LZW TIFF was *larger*? It can be if there is a _lot_ of detail. In a lossless compression scheme, the chances of a compressed image being _larger_ than the original are always equal to the chances of it being smaller, if the image is completely random. In practice, totally random images are scarce, but the more detail an image contains, the more closely it approaches randomness, and the greater the probability that the compressed file may actually be larger than the uncompressed file. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Density vs Dynamic range
Hi Laurie, The first point of confusion in your discussion with Austin appears to be that what you are referring to as dynamic range he is referring to as density range or that you are using the two terms synonomously while he is using them as naming two different concepts. Dynamic range is, in our case, (dMax - dMin) / noise. Density range is simply dMax - dMin. Dynamic range is the number of discernable values within a density range (in our case). Density range is simply the max density value you can get minus the minimum density value you can get. For instance, if I may take the liberty to put words in his mouth, take the statement: If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. I think apart from maybe disagreeing with the value coming from the CCD, he would say that what you are saying should read: If we double the number of bits (possible values) that doesn't increase the DENSITY RANGE of the scanner, only it's ability to represent accurately the DYNAMIC RANGE value CAPTURED AND DIGITALIZED by the scanner's analog to digital converter. Well, you HAVE to increase the scanners dynamic range for more bits to increase the ability to represent accurately the value coming from the CCD, assuming, as I've said that the number of bits was matched to the dynamic range of the CCD in the first place. Doubling the number of bits also does not increase the density range of the scanner, and it also doesn't increase the ability to represent accurately the dynamic range (as I said above). (Austin, if you are reading this and I am putting the wrong spin on it or words in your mouth, please feel free to correct me.) Yeah, I think things are being confused a bit (sic ;-)... Too bad ;-( It's really quite simple. Regards, Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
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[filmscanners] RE: Density vs Dynamic range
Plain and simple, do you agree that a dynamic range of 5000:1 REQUIRES 13 bits to represent every integer value between 1 and 5000? If so, then where's the problem? If not, then plain and simple, why not? Austin Hi Peter, Sorry if I sounded a bit surely in my last response. I'll try to straighten you out without getting surely again ;-) I think where we differ is the assumption the a 5000:1 dynamic range yields 5000 discrete integer values. Well, it does, that's in and of what a 5000:1 dynamic range means! Light intensity is a linear value so that 5000:1 range can be divided into as many steps as you'd like to use. Absolutely not true. The 1 is the noise floor, and you can not discern below the noise floor, and you can only discern in increments OF the noise floor. The noise floor IS the increment. It is in any case only a ratio and therefore has no units or integer values. If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. No, increasing the number of bits does not increase the dynamic range of the scanner, NOR does it increase the ability to represent accurately the value coming from the CCD, providing you already have enough bits TO represent the full dynamic range of the scanner. Assuming you already have enough bits TO represent the full dynamic range of the scanner, adding more bits simply means more bits are in the noise. If you believe what you say in the above paragraph, then I'd have to say you do not understand what dynamic range is, and what it means. If you don't increase the dynamic range out of the scanner, more bits will NOT give you more usable data...as I said, they will simply be in the noise. If not, then your statement is still wrong, or at best, an over-simplification. It's (my initial statement you disagree with) hardly an over-simplification, in fact, it is about as complete and accurate as you can get. It is a plain and simple fact that a dynamic range of 5000:1 requires 13 bits to represent that full dynamic range. Again, 1 is the first discernable signal (as in the noise floor), and since you can only measure in increments OF the noise floor...a dynamic range of 5000:1 simply means you can have every integer value from 1 to 5000...and to represent every integer value from 1 to 5000, you need 13 bits. I'm sure you'll agree that it's the noise floor and the saturation level that define the true dynamic range. Yes, and if you know that than I am miffed you say that my statement is wrong, because it says the EXACT same thing. You can only differentiate values that are different by the level of the noiseand it appears you somehow believe you can differentiate to a finer degree than the noise, which you can not. Simply put, dynamic range is the (max value - min value) divided by noise. That is the maximum number of differentiable values you can get. You can't measure half the noise, because your unit of measure IS noise. Regards, Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
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[filmscanners] Re: Sharpening and JPEG/TIFF (was: Color spaces for different purposes)
This is why you should never apply the unsharp masking on your high-res scans until the final target use of the image is known, and, if necessary, the image is resampled down for that use. For example, if you print a 360dpi image on a high quality inkjet printer on glossy media, you would need just a little unsharp masking, whereas printing the same image on offset press where the 4-color process screening will make images appear much softer you would need to apply a much stronger unsharp mask for the same final apparent crispness. If this same image was used for web, you would first downsample it to 72dpi, then unsharp mask it for appropriate level of crispness at that resolution. Sami While I agree with what you say, the reason for it is wrong. 72dpi has no meaning for screen viewing. Only the pixel dimensions are relevant. Screens don't know dpi or ppi. They only show pixels. Obviously, applying the same degree of sharpening to a 3000x2000 pixel image and to a 800x600 pixel image will have drastically different results. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Density vs Dynamic range
Dynamic range is, in our case, (dMax - dMin) / noise. I guess I tend to want to stay away from that definition in part because I am not really able to visualize it very well; but I can visualize Dynamic range is the number of discernable values within a density range (in our case) much better so I tend to favor this definition over the other. Just a case of my limitations getting into the act. Sorry. :-) Well, you HAVE to increase the scanners dynamic range for more bits to increase the ability to represent accurately the value coming from the CCD, assuming, as I've said that the number of bits was matched to the dynamic range of the CCD in the first place. Doubling the number of bits also does not increase the density range of the scanner, and it also doesn't increase the ability to represent accurately the dynamic range (as I said above) Alas, you are beginning to lose me because of my limited technical engineering knowledge - I suspect - with your first paragraph. With respect to the first part of the second paragraph, I understand what you are saying and I agree, for what it is worth. However, my understanding and agreement with the second part of this paragraph may turn on the terminological use of the notion of accurrately. If I understand what you have been saying, I can see that the number of bits has no bearing on accuracy of representation in the literal corrspondence notion of truth sense; but in a more figurative sense where the terms accuracy of representation stand for ability to define the density range in terms of finer gradiations or more descrete segments, I would suggest that it does increase the ability to discern and designate finer differences within the the density range. Unfortunately, I think the confusion stems from your desire to use the key terms in their very precise technical sense as defined in engineering formulas and concepts whereas I am only able to really grasp the general theoretical sense of the concepts in more metaphorical meanings. Nevertheless, I really appreciate the time everyone is taking to nurse me along in my attempt to decipher the discussion. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Austin Franklin Sent: Sunday, June 09, 2002 10:15 PM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: Density vs Dynamic range Hi Laurie, The first point of confusion in your discussion with Austin appears to be that what you are referring to as dynamic range he is referring to as density range or that you are using the two terms synonomously while he is using them as naming two different concepts. Dynamic range is, in our case, (dMax - dMin) / noise. Density range is simply dMax - dMin. Dynamic range is the number of discernable values within a density range (in our case). Density range is simply the max density value you can get minus the minimum density value you can get. For instance, if I may take the liberty to put words in his mouth, take the statement: If we double the number of bits (possible values) that doesn't increase the dynamic range of the scanner, only it's ability to represent accurately the value coming from the CCD. I think apart from maybe disagreeing with the value coming from the CCD, he would say that what you are saying should read: If we double the number of bits (possible values) that doesn't increase the DENSITY RANGE of the scanner, only it's ability to represent accurately the DYNAMIC RANGE value CAPTURED AND DIGITALIZED by the scanner's analog to digital converter. Well, you HAVE to increase the scanners dynamic range for more bits to increase the ability to represent accurately the value coming from the CCD, assuming, as I've said that the number of bits was matched to the dynamic range of the CCD in the first place. Doubling the number of bits also does not increase the density range of the scanner, and it also doesn't increase the ability to represent accurately the dynamic range (as I said above). (Austin, if you are reading this and I am putting the wrong spin on it or words in your mouth, please feel free to correct me.) Yeah, I think things are being confused a bit (sic ;-)... Too bad ;-( It's really quite simple. Regards, Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
I was thinking only of archived photos. For Web and e-mail use, in most cases you can crank the compression all the way up in Photoshop (that is, set it down to 1, the highest compression setting) and the image will still look fine. Unlike some editing programs, Photoshop won't let you compress the image so much that it really looks bad on the screen; even the worst setting is still pretty good. Disagree. I can make some pretty horrendous looking JPEGs at the lowest setting. Easy to see diff using Save For Web feature in PhotoShop. Additionally, with the lowest compression settings of Photoshop (level 10), I have yet to be able to distinguish between the original and the JPEG in terms of image detail, even when greatly magnifying the image. Maybe not on monitor, but printing reveals the diff. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Color spaces for different purposes
We may have taken separate paths to get there; but I believe that we both reached the same conclusion for either different reasons or by using different means of expression. :-) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Sunday, June 09, 2002 8:16 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Color spaces for different purposes Laurie writes: In practice, I do not think they are seperable so as to allow some other action to be carried out between the two processes, although it may be theoretically possible. JPEG encoding requires the rough equivalent of a Fourier transformation on the data; once that is undertaking, bitmapped operations on the image are no longer possible. So one cannot really separate them. Not all encoding formats impose this constraint, but I haven't heard of any software that separates the two processes, just the same. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
Date sent: Sun, 9 Jun 2002 19:42:32 -0500 Send reply to: [EMAIL PROTECTED] From: Maris V. Lidaka Sr. [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject:[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) It's not that unusual, though I don't recall why, and LZW compression will not reduce file size nearly as much as JPG Maris Makes sense to me. Even at low compression (high quality) a JPEG is throwing away alot of similar color nuances. That's how it works. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
David, I am not an engineer so I could very well be using terms that have techincally precise meanings in imprecise commonsense everyday fashions. By raw data, I only meant to designate the original data captured by the scan prior to any compression; and thus, I was only trying to say that if one is using lossy compression processes even at their minimum levle of compression there must in principle be some loss of information so there theoretically in principle must be more detail in the pre-compression data than in the post compression data even if it is of no practical significance. After some posts by Anthony, it has become clear that he was talking in for all practical purposes terms much like you are and with which I agree. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of David J. Littleboy Sent: Sunday, June 09, 2002 8:10 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for different purposes] Laurie Solomon [EMAIL PROTECTED] asked: Scans do not contain more detail than a low-compression JPEG can hold. This statement I do not understand; please elaborate. Surely, this cannot be the case if we are talking about raw data as opposed to encoded compressed data even at the lowest setting in which there still is some compression of the raw data. The raw data is not truly random data. It is actually smoothly changing nearly continuous data. So there is a lot of room for lossless compression. Low-compression JPEG is very close to lossless compression, and only loses information in areas of high detail and contrast. Since raw scan data doesn't have such areas, JPEG works well. David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen (was:Color spaces for differentpurposes)
Is it not lzw compression instead of lwz? Yes, my fingers went faster than my mind when I wrote it. :-( Your comment that lzw compressed TIFF files are as small as JPGs made me wonder if you are working with graphic files and if they offer better compression than photos. I must be candid and note that I was only repeating what others have said in other discussions of file compression techniques and their comparative advantages and limitations. I personally tend to use Genuine Fractals with photographic images and not JPEG or LZW. My experiences in doing some of my own testing suggests that (a) it depends on the image as to how comparable the size of the file will be upon compression using LZW vr JPEG at level 10-12, (b) the level of quality (i.e., degree of artifacting and degradation of the image) often is dependent on the degree of compression one uses when saving as JPEG such that the compression needed to produce sizable reductions in file sizes tends to result in a trade-off with respect to an increase in image degradation, and (c) certain image enhancements do prior to compression tends to effect the efficiency of the compression performed by the different compression operations. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Johnny Johnson Sent: Sunday, June 09, 2002 2:10 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: Although I concur with all you have said, I have to wonder if the publicist and publisher are requesting jpeg files rather than lwz compressed TIFF files out of force of habit, lack of knowledgabout the ability to compress TIFFs using the lwz compression which is as good if not better than the JPG compression at levels 10-12, or a lack of any real concern over quality of the file they are getting. Hi Laurie, Is it not lzw compression instead of lwz? In any case, does the amount of reduction in the file size using lzw compression vary considerably with the content? The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Your comment that lzw compressed TIFF files are as small as JPGs made me wonder if you are working with graphic files and if they offer better compression than photos. Later, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes)
Date sent: Sun, 09 Jun 2002 18:59:45 -0400 Send reply to: [EMAIL PROTECTED] From: Johnny Johnson [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject:[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes) At 05:32 PM 6/9/02 -0400, Mac wrote: Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Hi Mac, Thanks for asking - it looks like the original TIFF file that I grabbed must have already been saved with lwz compression. So, I did the experiment again using a fresh scan of a different slide with the following results: TIFF: 56,264 kb TIFF with lzw compression: 35,364 kb JPG with Photoshop level 12:18,453 kb So, in both this case and the previous one, the JPG with level 12 compression is ~ 1/2 the size of a TIFF with lzw compression. Thanks again for bringing my mistake to my attention, Johnny That makes more sense. Contrary to what Anthony Atkielski wrote, I have NEVER seen a LZW Tiff come out larger than an uncompressed one, regardless of exact pixel content. I have also never seen a compressed TIFF come out equal to or smaller than a JPEG at the same pixel dimensions, regardless of how how the quality setting of the JPEG. The only time I've seen a compressed file come out larger than a non-compressed one is when using .zip on a JPEG. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]
Your clarification has helped; and I have no significant disagreement with the gist of your statements now that I understand what you are saying and what you are using as your reference criteria. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Sunday, June 09, 2002 8:14 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for different purposes] Laurie writes: I agree with this; but in many if not most cases, the compression level used or required is greater then the lowest possible amount, ranging from level 6 to level 3 in order to get the file small enough to be an email attachment or a web site download. I was thinking only of archived photos. For Web and e-mail use, in most cases you can crank the compression all the way up in Photoshop (that is, set it down to 1, the highest compression setting) and the image will still look fine. Unlike some editing programs, Photoshop won't let you compress the image so much that it really looks bad on the screen; even the worst setting is still pretty good. This statement I do not understand; please elaborate. Most scans, at full resolution, do not actually hold enough detail to make full use of that resolution, so compressing them into JPEGs really doesn't sacrifice anything. Additionally, with the lowest compression settings of Photoshop (level 10), I have yet to be able to distinguish between the original and the JPEG in terms of image detail, even when greatly magnifying the image. Photoshop is very conservative. Surely, this cannot be the case if we are talking about raw data as opposed to encoded compressed data even at the lowest setting in which there still is some compression of the raw data. There is always some loss in a mathematical sense and a strict sense, but in practice you won't be able to see the loss when storing full-resolution scans as JPEGs with the quality setting set as high as it will go. I've never had any problem losing detail in archived JPEGs as long as I use the highest quality setting. I sure would like to see a 16-bit version of the JPEG standard, though. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Sharpening and JPEG/TIFF (was: Colorspaces for different purposes)
At 08:42 PM 6/9/2002, wrote: If this same image was used for web, you would first downsample it to 72dpi, then unsharp mask it for appropriate level of crispness at that resolution. While I agree with what you say, the reason for it is wrong. 72dpi has no meaning for screen viewing. Only the pixel dimensions are relevant. Screens don't know dpi or ppi. They only show pixels. Yes, sorry; I rewrote that part and looks like left out the obvious. Should have said: first downsample it to the pixel dimensions you need. --Sami Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen(was:Color spaces for differentpurposes)
I have occasionally gotten JPEGs that were larger than the original, uncompressed TIFF file if the file contained a lot of detail and had been heavily sharpened, and the JPEG compression was set at maximum quality / minimum compression. So it can happen, but in my personal experience only rarely. - David -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 PM [snip] The only time I've seen a compressed file come out larger than a non-compressed one is when using .zip on a JPEG. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Sharpening and JPEG/TIFF (was: Color spaces fordifferent purposes)
I think you should reread what Ken and I are saying - the effect of sharpening is more visible in a low res image, no more no less. Your lengthy explanation below is helpful in explaining why it is more visible. Thank you for that. The original response sailed by his question and I was re-emphasizing his observation. Don At 05:23 PM 09/06/2002 -0700, you wrote: Don, your support of Ken is a bit misplaced. TIFF vs. JPEG is non sequitur, Anthony is correct. This is about the pixels in the image, not about the file format in which it's saved. When an unsharp mask (a.k.a. sharpening) is applied to an image, it is enhancing the contrast of edges or areas of rapid level transition by lightening the light side, and darkening the dark side. This is done to the actual pixels in an image, independent of the image size resolution setting. The software analyzes the image and applies the sharpening effect within a certain pixel distance; this is the Radius setting in Photoshop's Unsharp mask, a typical distance could be e.g. 0.7 pixels. If you open your 27 MB file and the low res catalog scan, then apply the same unsharp mask to both, the edges enhancement is applied to the same distance in pixels around that edge in the image. These pixels, however, represent quite different distance in the image. If you view both at 100% resolution, and both happened to have a narrow feature 3 pixels wide in both, they both would be appear sharpened exactly the same. Now, naturally, a feature 3 pixels wide in the low-res image would be something close to 15 pixels wide in the high-res image. Therefore the edge-enhancing effect would appear much more pronounced on the low-res one. If you compared them side-by-side, your catalog scan might be all visible in the window when viewed at 100%; while the high-res would have to be zoomed out to 20% of actual, and the sharpening effect would be miniaturized on screen and be far less noticable. This is why you should never apply the unsharp masking on your high-res scans until the final target use of the image is known, and, if necessary, the image is resampled down for that use. For example, if you print a 360dpi image on a high quality inkjet printer on glossy media, you would need just a little unsharp masking, whereas printing the same image on offset press where the 4-color process screening will make images appear much softer you would need to apply a much stronger unsharp mask for the same final apparent crispness. If this same image was used for web, you would first downsample it to 72dpi, then unsharp mask it for appropriate level of crispness at that resolution. Sami Ken wrote: ... but could someone offer a technical explanation of why sharpening has so much more visible effect on jpegs as opposed to TIFFs? At 10:22 AM 09/06/2002 +0200, Anthony wrote: It doesn't. On Sunday, June 9, 2002, at 07:46 AM, Don Marcotte wrote: I support Ken. I'm currently scanning a large number of rolls of negative film. They are just 10x.6.67 inch by 72 ppi images for screen display. I'm keeping them in an electronic catalog of my images. Unless something has changed in Photo Shop 7, which I recently acquired, sharpening is much more noticeable on these small JPEGs than on 27MB TIFFs that I use for printing or creating slides. I would like to emphasize the word visible in Ken's question. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
