I did some tests when we first got our dye sub (300 dpi Tektronics).  I
found that for gray scale gels and blots, even 150dpi was overkill but I
use that routinely now (this assumes printing at 1:1 or less for the final
output.  Usually given the size of images in journals, we are reducing
original gels and blots. I always encourage users of our facility to decide
how large they want it to look in the journal before doing anything as that
determines what scan resolution you need.).  For color or complex images,
the dogma is that you should be at 2-4x the resolution of the printer, but
I have found 300dpi to be adequate for everything that I have tried to do.
It really depends on the images, but I agree that it is easy to overdo it.
Dave

>To:  Anyone who knows anything about digitized images, scanners, and printers.
>From:   Michael Ligorio, Ph.D.
>        University of Miami
>        Department of Physiology and Biophysics
>
>
>We have a Kodak dye-sublimation printer in our department.  I
>use flatbed and 32mm scanners to digitize photographs and
>negatives.  I adjust these images in Photoshop and then
>print them on color film paper.
>
>As you know, the higher the number of pixels/inch in each
>image the larger the resulting file.  Unfortunately, larger
>files take longer to save, print and process in Photoshop.
>
>Because of this inconvenience, I do not want to make files
>any larger than necessary.  Assuming I don't change the size
>of the original print, what is the mimimal scanning resolution
>that will result in the sharpest possible picture, if the printer's output
>limit is 300 dpi?  And, if I want to make the final print, for example,
>twice as many square inches in size as the
>original, by how much should I increase the scanning
>resolution?
>
>Please respond to the group or to my email [log in to unmask]
>
>Jody Myers, Ph.D.
>University of Miami School of Medicine
>Department of Physiology and Biophysics (R-430)
>4045 RMSB
>Miami, FL  33136
>305-243-6769
>2343 Tigertail Ave.
>Miami, FL 33133
>305-285-4721


Dr. David Knecht
Department of Molecular and Cell Biology
University of Connecticut
U-125
Storrs, CT 06269
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