[alt-photo] Re: imagesetter

Loris Medici mail at loris.medici.name
Fri Nov 30 18:14:48 GMT 2012

Scott, I extensively used imagesetter negatives some 7-8 years ago,
what's your question/problem?

Short notes below:
- The imagesetter hardware resolution was 3600 dpi
- Therefore, I used a 3600 / 16 = 225 lpi screen resolution (That's
for being able to get 16 x 16 = 256 distinct dot values... Best to use
a imagesetter that has 4800 dpi hardware resolution, because 4800 dpi
= 16 x 300 lpi, the higher the screen resolution the better the
negative will be. OTOH, too high resolutions are problems for the
imagesetters, the particular unit has to be in perfect condition / has
to be in perfect calibration status!)
- The screen was using elliptic dots and the angle was 45 degrees
- The file that you're going to feed the imagesetter has to have at
least two times the resolution of the target screen resolution (e.g.
if target screen resolution = 225 lpi then the digital image file has
to have 225x2 = 450dpi resolution and likewise...)
- I was using the negatives emulsion up because it gave me different
tones between places that had perfect contact between the negative and
paper and places that had less than perfect contact. Since the
negative material is relatively thin, there wasn't a too bad sharpness
loss. (In short: Try printing emulsion down first, if you experience
uneven density in monotone areas or areas with very smooth tonal
transitions, then try emulsion up...)

Hope this helps!


2012/11/30 Weber, Scott B <sweber at mail.barry.edu>:
> Anybody using an imagesetter to make negatives from digital files? Any info will help.

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