FotoDave@aol.com
Sat, 17 Apr 1999 02:11:21 -0400 (EDT)
In a message dated 4/16/99, PM 03:59:44, alt-photo-process-l@skyway.usask.ca
writes:
<<Then with the foreground color set to the default 100% black and the
background color set to the default while, use the Gradient tool in
the tool box to create a ramp.
Then select Image: Map, Posterize from the menu and posterize it in 21
levels if you want 5% increments. Now you have a ramp you can send to
an output device to check calibration. The value requested in
photoshop should be the value read by a densitometer.
>>
Jeff,
The authors of Photoshop books usually works with printers or service bureaus
which use "graphic arts densitometer." That type of densitometers give the
reading in percent coverage rather than in density, so one can say that "the
value requested in
photoshop should be the value read by a densitometer."
Most of us have densitometers that give density value. Of course one can
convert from one to another, but as I said in my other post, the easiest way
is to plot density vs. log(rgb) which will basically take care of the
conversion.
Dave S
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