which pixel resolution for slide scans?

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Tim923

I'm wondering which pixel resolution to use for slide scan bitmaps and
JPEGs. 800x600, 1024x768, 1152x864, 1365x1024? At what point is it
overkill? I haven't tried the scanner yet, but I think it scans by
dots per inch resolution, so I might not be able to set the pixels.

-
http://mysite.verizon.net/vze8adrh/news.html (profile) --Tim923 My email is valid.
 
Tim923 said:
I'm wondering which pixel resolution to use for slide scan bitmaps and
JPEGs. 800x600, 1024x768, 1152x864, 1365x1024? At what point is it
overkill? I haven't tried the scanner yet, but I think it scans by
dots per inch resolution, so I might not be able to set the pixels.

-
http://mysite.verizon.net/vze8adrh/news.html (profile) --Tim923 My email
is valid.
Click to expand...

Most of your questions can be answered by reading:
http://www.scantips.com/

The short answer is, it depends on the end use for the scan.

If you are going to archive the slides, then scan at the max resolution that
you can and that you have the storage space for.

3200 dpi or 4000 dpi will make huge files.

A 35 mm Slide scanned at 3200 dpi makes a 4680 X 3120 pixel image and a 41.7
MB Tiff file or a 1.20 MB Jpeg saved at 75 Quality.
 
All of those sizes are massive underkills. By the way, scanner dpi is the
same as pixels per inch.
Jim
Tim923 said:
I'm wondering which pixel resolution to use for slide scan bitmaps and
JPEGs. 800x600, 1024x768, 1152x864, 1365x1024? At what point is it
overkill? I haven't tried the scanner yet, but I think it scans by
dots per inch resolution, so I might not be able to set the pixels.

-
http://mysite.verizon.net/vze8adrh/news.html (profile) --Tim923 My email
Click to expand...
is valid.
 
Tim923 said:
I'm wondering which pixel resolution to use for slide scan bitmaps and
JPEGs. 800x600, 1024x768, 1152x864, 1365x1024? At what point is it
overkill? I haven't tried the scanner yet, but I think it scans by
dots per inch resolution, so I might not be able to set the pixels.
Click to expand...
If you have the processing power and storage capacity then always scan
at the maximum optical resolution of the scanner and then downsample the
result to the required size for your application using the best
resampling algorithm you can readily obtain.

For the film scanners on the market at the moment, assuming decent
quality film originals, it only becomes overkill when you are scanning
at *more* than the optical resolution of the scanner.
 
I've scanned heaps of slides and various size negatives. To give my 2c worth
I've found that rule-of-thumb is to simply setup to give a tif file of
around 25 megs regardless of what I'm scanning - that covers the field for
anything I want to do up to a very nice 8" x 10" print.
Cheers
Dave
 
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