[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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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: 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 - Original Message - From: Laurie Solomon [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, June 08, 2002 8:34 PM Subject: [filmscanners] RE: Color spaces for different purposes [snipped] conversion from TIFF to JPG reduces file size and apparently compresses, I would think to Maximum quality. Sharpening at that point was what I was suggesting, before saving as a more-compressed JPG Saving a file as a JPG file at a level of compression involving the least amount of compression would obviously result in much less lost empirical information (e.g., actual image data) than to save at higher compression levels; however, I think it is questionable if the remaining empirical data would represent maximum quality in all cases. But to change the existing data in the original JPG file by sharpening and then resaving the result to a more compressed state is one of the sorts of actions which tends to produce the often found JPG artifacts and deterioration of the image that such a file can produce. [remainder snipped] 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 Sat, 8 Jun 2002 21:36:38 -0500, you wrote: 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. Well there may be other variables in my system, but I get fewer artifacts sharpening the reduced TIFF rather than the JPEG. I may need to experiment with lower USM settings on my JPEGs, but given my scanner's good somewhat limited capabilities (FS2710) , I'm very happy with the workflow of TIFFresize/resample sharpencompress. 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
