Digital BW, The Print

> From: Ken Carney [mailto:kcarney1@...]
>
> Good questions, Antonis.  I will have to approach this in a more
> structured
> way.  The PS color space (Adobe RGB 1998) and the Epson print space (Epson
> 2200 EEM MK, no color adjustment) are the same.  The files are RGB (Portra
> b&w C41 film, which scans with a slight color cast, so converted to b&w in
> PhotoKit).  The computer is a PC (Windows XP).   I didn't think
> to test both
> 8 and 16 bit files.  What I did was start with a 16-bit RGB scan
> that I had
> used to make an 8-bit print, and did similar contrast adjustments with CS,
> only now with 16-bit layers.  After drying, the prints (EEM) are pretty
> green under daylight, but fairly neutral under tungsten or fluorescent.  I
> would have thought that if the PS eyedropper tool is showing me that RGB
> values are equal, and I print on the same paper with the same profile,
> Photoshop would not influence the print.  But maybe not.  I'll work on it
> some more and report back.

Someone mentioned that Photoshop's algorithms for doing adjustment layers
have lots of shortcuts in them to make them more efficient, at the expense
of accuracy, since they were designed back when we were all running much
wimpier processors. And these shortcuts are probably retained in the latest
version, so that old fles opened in PS CS won't look different. But it's
possible that when they added 16-bit adjustment layers, they decided to do
the 16-bit versions of the calculations without these hacks, since they're
no longer necessary. If you still have PS7 installed, you might try some
simple tests to see if printing files without layers, or with 8-bit layers
only, exhibits the same shift between the versions.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...