Which DPI To Use When Scanning Film

None of the flatbed scanners can do more than 1800 or so dpi. You should select the value that is at or above that in your scanner software. Anything else just results in a larger image of no more resolution.

Tony-S wrote in post #11618644
None of the flatbed scanners can do more than 1800 or so dpi. You should select the value that is at or above that in your scanner software. Anything else just results in a larger image of no more resolution.

Not sure about 1800, but I agree that it's way less than the manufacturers state. This guy has a reasonable explanation:

http://www.scantips.co​m/chap3c.html

You can get as technical and esoteric as you want, but in the real world, it's a simple matter of determining how big a scanned image you want to end up with and back into the flatbed settings. You can calculate it or use trial and error. Test scans, unlike test prints, don't cost anything but a few minutes of your time.

And let's keep in perspective that the OP does not have a high end stand alone scanner, but an AIO device.

Scanning at 2400 PPI should give you a reasonable 8x10 print at 300 PPI. The choice of 48bit or 24bit quality are side issues.

ChasP505 wrote in post #11624084
You can get as technical and esoteric as you want, but in the real world, it's a simple matter of determining how big a scanned image you want to end up with and back into the flatbed settings. You can calculate it or use trial and error. Test scans, unlike test prints, don't cost anything but a few minutes of your time.

And let's keep in perspective that the OP does not have a high end stand alone scanner, but an AIO device.

Scanning at 2400 PPI should give you a reasonable 8x10 print at 300 PPI. The choice of 48bit or 24bit quality are side issues.

Correct, a 2400 scan will yield an 8x10 at 283 PPI as long as there is no cropping other than to get the 8x10 format. That's good enough for a decent print.

I always do some cropping and straightening so I like a bit higher resolution, but I also have a 4000 DPI negative scanner and a computer with enough horsepower to quickly handle some huge files in PS. Even then my cr@ppy stuff is all scanned as jpeg and I only use TIFF for something I'm proud of.

You give good advice regarding test scans. The OP may find that simple scans to jpeg at 2400 DPI are more than good enough for his use.

Most modern scanners scan at a much higher resolution than 2400dpi. For instance, the Epson V500 scans at 6400dpi optical and 12,800 interpolated as does the Canoscan.

The scanning settings I believe should be dependent on usage. If it's just to make a single scan for a 8x12 or 4x6 then 2400 dpi is just fine. But if your scanning to archive then I would scan at a much higher resolution.

I've been archiving all my old negatives and have chosen 4800dpi at 48 bits. It is a very long tedious process and I intend to do this only once. A 4800dpi scan give me a file about 6700 by 4700 pixels (about the size of a 5DII file) but they are big. (about 125meg). I got two 1t drives just for scanned photos, one online and one backup. A drive should hold about 8000 pics.

gjl711 wrote in post #11629425
Most modern scanners scan at a much higher resolution than 2400dpi. For instance, the Epson V500 scans at 6400dpi optical and 12,800 interpolated as does the Canoscan.

No, they don't - not the flatbeds. I have a V500 and it tops out at about 1800 dpi (maybe 2000 dpi). The companies use deceptive calculations when advertising the resolution of their scanners. When the US Air Force 1951 test target is used, the limitations of these flatbed scanners is exposed (no pun intended). They just can't compare to most dedicated film scanners.

gjl711 wrote in post #11629425
Most modern scanners scan at a much higher resolution than 2400dpi. For instance, the Epson V500 scans at 6400dpi optical and 12,800 interpolated as does the Canoscan.

All well and good, but the OP doesn't have a V500... He's got the scanner built into his AIO unit, and by design, each component of AIO devices has compromised performance limits.

ChasP505 wrote in post #11631897
All well and good, but the OP doesn't have a V500... He's got the scanner built into his AIO unit, and by design, each component of AIO devices has compromised performance limits.

Well I started the thread and I feel that my Canon MP990 does a real nice job of scanning film, at least it is very acceptable to me, but I haven't got around to printing an 8x10. That will determine what dpi I'll use depending on IQ of the 8.10. It will scan up to 4800dpi but I think it would take forever to scan a track of 4 negatives. The printer came with negative/slide holders that lock into the scanning bed and can do either 4 negatives or slides at one time. Just scanning 4 at 1200dpi took quite some time. I do wish to thank everyone for all their input....such an informative group of people here, just a great site.

Tony-S wrote in post #11618644
None of the flatbed scanners can do more than 1800 or so dpi. You should select the value that is at or above that in your scanner software. Anything else just results in a larger image of no more resolution.

Are you sure of this? Right now I am looking at the options (using VueScan and an Epson V7000 Photo). This is what I see: 6400 dpi, 3200, 1600, all the way down to 100 dpi. Also, from 64 bit RGBI down to 1 bit B&W.

Rafromak wrote in post #11637326
Are you sure of this? Right now I am looking at the options (using VueScan and an Epson V7000 Photo). This is what I see: 6400 dpi, 3200, 1600, all the way down to 100 dpi. Also, from 64 bit RGBI down to 1 bit B&W.

What ya' see and what ya' get are 2 different things.

I'll be doing 33mm negs on an epson v600. Goal is permanent archive of files to print as large as possible (perhaps about 24" on longest side).

Question:

Is a scan to a jpeg at (high or max) quality setting really that noticeably inferior to a tiff and is it worth the quality / disk space trade off? (any PS editing from the scanned jpg would never be saved back as jpeg, but psd).

Picture North Carolina wrote in post #11638412
Is a scan to a jpeg at (high or max) quality setting really that noticeably inferior to a tiff and is it worth the quality / disk space trade off?...

Noticable is such a loaded word. It will be to some and wont to others. It is fact that jpeg does compress the image so at some pixel peeping level you can see the jpeg artifacts. You also save only 8 bits of color info so gradients will not be as smooth. These might become noticeable on larger prints.

gjl711 wrote in post #11638459
Noticable is such a loaded word. It will be to some and wont to others.

Thanks for the reply. Yes, agree on the word "noticeable." It's highly subjective. I've done 24x36 prints from 20D files that received glowing feedback, whereas to me the quality was very unacceptable.

I very rarely have a need to print small. Most everything is 16x20 or larger so I guess I'll just have to sacrifice the disk space.

Picture North Carolina wrote in post #11638501
I very rarely have a need to print small. Most everything is 16x20 or larger so I guess I'll just have to sacrifice the disk space.

Disk space is so cheap these days. I've seen 1t drives for ~$60 and 2t drives for under $100. A 2t drive can hold about 16,000 decent size tiffs.

(back to the resolution debate...)

I understand what is being said about flatbed optical resolution exaggerations.

That being said and accepted, would it not be safe to say that scanning a neg at up to the manufacturer's stated optical resolution would be safe and produce the best quality?

Case in point: the v600 optical resolution is stated as 6400. If my math is correct, a neg at 6400 and printed at my printer's native resolution (360) would net an image approx 17.5" on the short side. Correct? (disregard file size).

If so, then scanning at 4800 would produce an approx. 13" which I would find acceptable if the 6400 file size is too large.

Would this be the best way to go with the eventual goal being large prints?