filmscanners: Figuring out size & resolution
I just bought a Epson 1270SU. Is there a formula for picking density and output size based on input size and projected print size. I scan 6x7 and will print either 8x10 or 11x14 And I scan 35mm and will print either 8x(10/12) or 11x(14/16) If I specify my output size, how do I decide what density to pick? Thanks Rick Decker
RE: filmscanners: Figuring out size & resolution
A very good place to get information on size and resolution (and much more) is: http://www.scantips.com /fn -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Rick Decker Sent: Saturday, July 07, 2001 12:51 PM To: [EMAIL PROTECTED] Subject: filmscanners: Figuring out size & resolution I just bought a Epson 1270SU. Is there a formula for picking density and output size based on input size and projected print size. I scan 6x7 and will print either 8x10 or 11x14 And I scan 35mm and will print either 8x(10/12) or 11x(14/16) If I specify my output size, how do I decide what density to pick? Thanks Rick Decker
Re: filmscanners: Figuring out size & resolution
Rick, I'm not sure exactly what you mean by "density," but not knowing what the question is has never stopped me from giving an answer before. I'll assume that density means the number of dots per inch (dpi) that you send to the printer. There's another value that has to do with how many dpi the printer actually prints on paper, such as 1440 dpi. But that value is printer specific. My Epson 2000P doesn't even let me set that value. It gives me a choice of printing at "photo quality" speed or "high speed" and adjusts the number of "dots" on the paper accordingly. My recommendation is that you tell your printer to print on paper at the highest number of dots per inch your printer is capable of (1440?) so as to get the best "photo quality" and that you send the image to the printer at 300 dpi. I'd also recommend you check out www.scantips.com for related information. Most printers are happy if they are fed data at a "density" of 300 dpi. With less than that the print quality suffers. With more dpi than that, it's just a waste of good pixels and the print quality isn't any better than if 300 dpi were used. I've read on this list that some of the cheaper printers don't improve past about 240 dpi and there are some that don't stop improving until you pass 360 dpi. But a good rule of thumb is to use something close to 300 dpi. For example, assume that you scan a 35 mm slide with a scanner that scans at 4000 dpi. If the slide is 1x1.5 inches in size (it's a bit smaller due to the mount, etc., but this makes the math easier), then you'll have an image that's 4000x6000 pixels. The maximum size of print you can make from that image is found by dividing the 4000 and 6000 pixel dimensions by 300 (the dpi you need to send to your printer). And the answer is: 13.33x20.00 inches. So that's the largest print that you can get and still have at least 300 dpi worth of data to send to your printer. If you try to print something bigger than that, you'll be forced to send less than 300 dpi to the printer and the print quality will go down. But, suppose you want to an 8x12 print. Divide 4000 by 8 (or 6000 by 12) and you find that you'll be sending 500 dpi to the printer. That's more dpi than you really need, but it won't hurt anything. (I've heard on this list that using more dpi than necessary uses more ink, but I don't think that's true. Maybe someone on the list can enlighten me.) You can do your calculations in reverse, also. For example, if you want to make an 11x14, then multiply each of those numbers by 300 and you'll find that you need an image that's at least 3300x4200 pixels in size. So if you have a 4000x6000 pixel image, then you've got more than enough pixels for a good print. In fact, you might want to "throw away" some of the unneeded pixels if you want to save a copy of the print on your hard drive since the file size would be smaller. To do that you resize the 4000 dpi, 4000x6000 pixels, 1x1.5 inch original image so that it becomes 300 dpi, 3300x4200 pixels, and 8x12 inches. Remember, though, that once you resize an image in such a manner that pixels are thrown away, you can't resize back up to an image with the original number of pixels. I hope I answered your question. If not, restate it and I, or someone else, will try again. In a message dated 7/7/2001 12:06:08 PM Pacific Daylight Time, [EMAIL PROTECTED] writes: I just bought a Epson 1270SU. Is there a formula for picking density and output size based on input size and projected print size. I scan 6x7 and will print either 8x10 or 11x14 And I scan 35mm and will print either 8x(10/12) or 11x(14/16) If I specify my output size, how do I decide what density to pick? Thanks Rick Decker
Re: filmscanners: Figuring out size & resolution
Ray wrote me (Roger) off line concerning my last post: Roger, your message to the group needs to be corrected. dpi is printer resolution (dots per inch) ppi is image resolution (pixels per inch) Your printer will print at 1440 dpi. Your computer will send a 300 ppi image to your printer for it to print at 1440 dpi. In your message, you need to change everything to ppi except the 1440 dpi for your printer. Hope you don't mind if I send this directly to you. Ray Amos You're right, Ray. I know better, too. Hope I didn't confuse anyone. And, most important, I hope that Rick is able to figure out what he needs to know as an answer to his question. Roger Miller In a message dated 7/7/2001 12:06:08 PM Pacific Daylight Time, [EMAIL PROTECTED] writes: I just bought a Epson 1270SU. Is there a formula for picking density and output size based on input size and projected print size. I scan 6x7 and will print either 8x10 or 11x14 And I scan 35mm and will print either 8x(10/12) or 11x(14/16) If I specify my output size, how do I decide what density to pick? Thanks Rick Decker
Re: filmscanners: Figuring out size & resolution
I agree with Roger's advice, but bravely add the following.. 1. I have always seen many beginners, me included, get very confused about the (non-existent?!) link between image resolution (ppi) and 'printer resolution' (eg the 1440/720 dpi setting). As a starting point, I just recommend that you always set the printer to the highest quality setting for the paper being used. And then deal with the resolution of your image as a separate issue, using the approach outlined by Roger. On many printers (admittedly not so much on a 1270..) using low quality settings like 720 or 360 dpi just results in more noticeable dithering in pale areas - *no matter what the resolution of your image might be*. 2. If you are printing directly from an imaging program and/or working on a high-spec PC, extra resolution (and therefore size) of your image might not be an issue. But if the image is to be incorporated into a dtp document (in Publisher for example, which doesn't cope very well with large images), you may *need* to resize the image first. And if you are sharing a network drive in an office/education/.. environment, your network supervisor will appreciate smaller files, it will be quicker to send via the internet, ..etc. So there are many circumstances in which it pays to resize to suit the required output quality. My personal (amateurish) experience on my 1270 is that 300 ppi gives 'pro' quality, 200 ppi is adequate for 'normal' photo-quality (and the difference is quite difficult to spot on most images), 100 ppi is adequate for a poster size print not likely to be viewed close up, or a document that will only be seen in photocopied form. Lastly, the image content can also be a criteria - some shots, eg soft-focus, would probably not benefit from going over 75 ppi..!! :)(Hey, try it before you disagree!) Mark T, now ducking for cover..
Re: filmscanners: Figuring out size & resolution
I wasn't going to read this post, because I don't have an Epson printer (well, I do, but it doesn't do color). I'm glad I did, because the intro was both funny and informative. The rest was *very* informative, and I'm archiving it. Even if I don't print a lot, this makes such crystal-clear sense that I need to keep it. Thanks, Roger. Best regards--LRA >From: [EMAIL PROTECTED] >Reply-To: [EMAIL PROTECTED] >To: [EMAIL PROTECTED] >Subject: Re: filmscanners: Figuring out size & resolution >Date: Sat, 7 Jul 2001 17:54:12 EDT > >Rick, I'm not sure exactly what you mean by "density," but not knowing what >the question is has never stopped me from giving an answer before. I'll >assume that density means the number of dots per inch (dpi) that you send >to >the printer. There's another value that has to do with how many dpi the >printer actually prints on paper, such as 1440 dpi. But that value is >printer specific. My Epson 2000P doesn't even let me set that value. It >gives me a choice of printing at "photo quality" speed or "high speed" and >adjusts the number of "dots" on the paper accordingly. My recommendation >is >that you tell your printer to print on paper at the highest number of dots >per inch your printer is capable of (1440?) so as to get the best "photo >quality" and that you send the image to the printer at 300 dpi. I'd also >recommend you check out www.scantips.com for >related information. > >Most printers are happy if they are fed data at a "density" of 300 dpi. >With >less than that the print quality suffers. With more dpi than that, it's >just >a waste of good pixels and the print quality isn't any better than if 300 >dpi >were used. I've read on this list that some of the cheaper printers don't >improve past about 240 dpi and there are some that don't stop improving >until >you pass 360 dpi. But a good rule of thumb is to use something close to >300 >dpi. > >For example, assume that you scan a 35 mm slide with a scanner that scans >at >4000 dpi. If the slide is 1x1.5 inches in size (it's a bit smaller due to >the mount, etc., but this makes the math easier), then you'll have an image >that's 4000x6000 pixels. The maximum size of print you can make from that >image is found by dividing the 4000 and 6000 pixel dimensions by 300 (the >dpi >you need to send to your printer). And the answer is: 13.33x20.00 inches. >So that's the largest print that you can get and still have at least 300 >dpi >worth of data to send to your printer. If you try to print something >bigger >than that, you'll be forced to send less than 300 dpi to the printer and >the >print quality will go down. But, suppose you want to an 8x12 print. >Divide >4000 by 8 (or 6000 by 12) and you find that you'll be sending 500 dpi to >the >printer. That's more dpi than you really need, but it won't hurt anything. >(I've heard on this list that using more dpi than necessary uses more ink, >but I don't think that's true. Maybe someone on the list can enlighten >me.) >You can do your calculations in reverse, also. For example, if you want to >make an 11x14, then multiply each of those numbers by 300 and you'll find >that you need an image that's at least 3300x4200 pixels in size. So if you >have a 4000x6000 pixel image, then you've got more than enough pixels for a >good print. In fact, you might want to "throw away" some of the unneeded >pixels if you want to save a copy of the print on your hard drive since the >file size would be smaller. To do that you resize the 4000 dpi, 4000x6000 >pixels, 1x1.5 inch original image so that it becomes 300 dpi, 3300x4200 >pixels, and 8x12 inches. Remember, though, that once you resize an image >in >such a manner that pixels are thrown away, you can't resize back up to an >image with the original number of pixels. > >I hope I answered your question. If not, restate it and I, or someone >else, >will try again. > >In a message dated 7/7/2001 12:06:08 PM Pacific Daylight Time, >[EMAIL PROTECTED] writes: > > > > I just bought a Epson 1270SU. > > > > Is there a formula for picking density and output size based on input > > size and projected print size. > > > > I scan 6x7 and will print either 8x10 or 11x14 > > > > And I scan 35mm and will print either 8x(10/12) or 11x(14/16) > > > > If I specify my output size, how do I decide what density to pick? > > > > Thanks > > > > Rick Decker > > > > _ Get your FREE download of MSN Explorer at http://explorer.msn.com
Re: filmscanners: Figuring out size & resolution
"Mark T." <[EMAIL PROTECTED]> wrote: [a bunch of stuff about printing] FWIW I always scan from the film scanner at full resolution (2700ppi with the LS30) and change the output (ie printed) resolution afterward. IMO it makes more sense to get the maximum off the film, and then figure out how to scale it afterwards in Photoshop or PSP. Rob
Re: filmscanners: Figuring out size & resolution
--- [EMAIL PROTECTED] wrote: > There's another value that has to do > with how many dpi the > printer actually prints on paper, such as 1440 dpi. > But that value is > printer specific. Good to point that out. > My Epson 2000P doesn't even let > me set that value. It > gives me a choice of printing at "photo quality" > speed or "high speed" and > adjusts the number of "dots" on the paper > accordingly. We probably don't have the same driver. Anyway, with my driver in the 'main' field of the print dialog I can chose between 'automatic' and 'custom'. Automatic only lets me chose between 'quality' and 'fast'. When I chose 'custom' and configure the settings I can specify the dpi incl. other settings. > My recommendation is > that you tell your printer to print on paper at the > highest number of dots > per inch your printer is capable of (1440?) so as to > get the best "photo > quality" and that you send the image to the printer > at 300 dpi. That's exactly what I do. But the highest resolution might not always be the best setting depending on the paper used. On some (cheaper) paper I seem to get worse result with the max setting. > Most printers are happy if they are fed data at a > "density" of 300 dpi. With > less than that the print quality suffers. With more > dpi than that, it's just > a waste of good pixels and the print quality isn't > any better than if 300 dpi > were used. I've read on this list that some of the > cheaper printers don't > improve past about 240 dpi and there are some that > don't stop improving until > you pass 360 dpi. But a good rule of thumb is to > use something close to 300 > dpi. > > But, suppose you want > to an 8x12 print. Divide > 4000 by 8 (or 6000 by 12) and you find that you'll > be sending 500 dpi to the > printer. That's more dpi than you really need, but > it won't hurt anything. I am not sure about that. If you send more dpi the printer (software?) has to downsample it. You might get better results if you let photoshop doing that. One reason for my thinking is that PS has better algorithms. But more important the sharpening should be done on the final resolution. So if you have too many dpi you first do sharpening and then downsampling instead of downsampling and then sharpening. I have to admit though that I never made any tests but always first downsample to 300dpi. One other reason why to keep the size of the printed data down is to reduce the amount of data that has to be processed and sent to the printer. > (I've heard on this list that using more dpi than > necessary uses more ink, > but I don't think that's true. Maybe someone on the > list can enlighten me.) Well, not sure about that but there might be some truth in that statement. When you set the printer to higher dpi it will print more pixels per inch. On one hand this will increase quality because now the printer can use more micro pixels to generate one pixel (the printer uses CMYK to produce 1 pixel. Some printers add another two colors which does increase accurecy further. Imagine you have a color that is between C and M. If you have an additional color that represents the value between C and M you need only one single micro-pixel. If you don't have it you need a C and M micro-pixel.). On the other hand printing more micro-pixels will use up more ink IF the droplet size is kept the same. Maybe the printer actually does decrease the droplet size for higher dpi but I have the impression this does not happen in a linear (or x^2) ratio. One indication might be that on regular paper the paper gets more 'currly' with higher dpi because it seems to get more wet (more ink). Robert __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/
Re: filmscanners: Figuring out size & resolution
On Sun, 08 Jul 2001 11:06:28 +0930 Mark T. ([EMAIL PROTECTED]) wrote: > 1. I have always seen many beginners, me included, get very confused > about the (non-existent?!) link between image resolution (ppi) and > 'printer resolution' (eg the 1440/720 dpi setting). Read the 'how much resolution do I need?' section at my site (Filmscanners|Scanner Issues|Choosing & Using|Resolution) (again:) Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons
Re: filmscanners: Figuring out size & resolution
On Sat, 07 Jul 2001 08:51:29 -1000 Rick Decker ([EMAIL PROTECTED]) wrote: > If I specify my output size, how do I decide what density to pick? Read the 'how much resolution do I need?' section at my site (Filmscanners|Scanner Issues|Choosing & Using|Resolution) Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons
Re: filmscanners: Figuring out size & resolution
Rob wrote: >FWIW I always scan from the film scanner at full resolution (2700ppi with >the LS30) and change the output (ie printed) resolution afterward. IMO it >makes more sense to get the maximum off the film, and then figure out how >to scale it afterwards in Photoshop or PSP. That's always worked for me, too. It doesn't make sense to save pictures at full resolution unless you're going to do further work on them (e.g. retouching or large prints). The flip side of that coin, of course, is that if you've already done the work of scanning, why not save it as scanned? If you have ample storage space, there's no reason not to--but given past discussions on the fallibility of inexpensive CD-R's, perhaps it would be better to save small "thumbnail" files to disc/or HD for reference and the large files to CD-R or DVD for later use. Just a thought. ---LRA _ Get your FREE download of MSN Explorer at http://explorer.msn.com
