I have a probably common situation: I have loads of old photos on paper and negative that I am thinking of converting onto CD rom for on-line viewing. Now, what resolution would be the right in order to not loose quality? I was planning of being able to print on photo paper again. The collection is ordinary 35mm and APS ASA 200..400, the usual mainstream stuff.

-- Harald Rudell (harald.rudell@ericsson.com), May 02, 1999

Answers

Herald: Sounds to me like you will want multiple resolutions. You say you want to eventually print on Photo Paper again, and you want these photos for on-line viewing. Unfortunately the resolution requirements of printing best photo quality, and on-line viewing are mutually exclusive. On line viewing will produce great results at about 150 to 300 DPI, then compressed as JPG's. Try to keep file sizes in the <100K range for on-line viewing if you want to present them on the web. You can go much larger than that if you are on a local LAN or are just viewing them on your computer. But even viewing them on your local computer can get tedious if your files are very large.

For later printing you will wind up with files that can exceed 30 megabytes each. Ouch! It depends on what size prints you want to print in the future. If you are talking 8 X 10 then you want lots of pixels (very large file size). If you are talking 3 X 5's then you can get away with much less.

For your formats a nice Nikon Coolscan with the APS adapter would be an excellent choice (a bit expensive perhaps). I have a Photosmart S20 - but it doesn't do APS (too bad - because for the price it's a tremendous film scanner - and it does prints up to 5 X 7 too).

BTW - losing quality is unavoidable. Negatives can produce resolution hundreds of times better then the most sophisticated scanner costing 10's of thousands of dollars. The exposure lattitude of film so far exceeds the lattitude of the best scanners (D - Range) that it's almost a laughable comparison. BUT - most of the resolution and lattitude tends to be unneccesary in most standard photography.

Des

-- Dan Desjardins (dan.desjardins@avstarnews.com), May 02, 1999.