A service bureau should be knowledgeable enough in graphic arts terminology to
not confuse dpi and lpi. The output resolution of an imagesetter is specified
in "DPI" or "dots per inch". The halftone screen ruling is specified in "LPI"
or "lines per inch". For the most part, these are mutually exclusive of each
other. The more important one for digital negatives is the LPI. This is the
frequency of the screening used to produce your image, which, remember , is
made up of only black dots and clear film. There are actually many imagesetter
pixels, or "dots" that make up a single halftone dot. This is the confusion
most people have. A service bureau will probably tell you that there maximum
screen ruling is 300 lpi or 425 lpi if they have an Agfa imagesetter. Those
ruling have to be output at 3600 dpi. If they don't have an imagesetter that
does 3600 dpi, they probably can't do those screen rulings. Try asking for
CristalRaster, either 14 micron or 21 micron size. For a digital neg, I'd
recommend the 14 micron size. They may not have that screening though, it
costs extra for them to buy the software. If anyone is still confused, or even
more confused, write me off line or call me and I'd be happy to explain all of
it in more detail.
Dave Romano
Agfa Corporation
978-658-0200 xt 5707
This archive was generated by hypermail 2b29 : Tue Jan 11 2000 - 12:10:48