Converting Slides to High-quality Web Images

Curtis Clark jcclark at CSUPOMONA.EDU
Fri Dec 15 17:49:26 CST 2000

One thing that no one mentioned at least on-list, and that may not be
relevant to Diana's situation, but is broadly useful otherwise, is to scan
at least twice the size (in pixels) you ultimately intend to use and then
resample to the final size.

For general web photography:

1. Scan or photograph to produce a large (in pixels) image.
2. Touch up as needed (to remove dust marks, scratches, inflorescences,
etc.--just kidding about the last one)
3. Adjust levels so that the darkest pixels are almost black, the lightest
almost white (unless the original didn't have that dynamic range), and use
gamma to adjust the midtones (there are even fancier techniques).
4. Resample to the ultimate size (in pixels) that you want on the web.
5. Do unsharp mask, if necessary, to further sharpen the photo.
6. Save as JPEG, either with a program that lets you view the result, or
else aim for a setting of 75 (25% compression).

Of course your mileage may vary.

Curtis Clark        
Biological Sciences Department             Voice: (909) 869-4062
California State Polytechnic University      FAX: (909) 869-4078
Pomona CA 91768-4032  USA                  jcclark at

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