Re: [APML] Photoshop questions

[Jerry Lodriguss <jerryapml@astropix.com>]

Hi Dale,


>1: What is the point of having the working space set to Adobe RGB 1998 if my
>monitor will only display the monitor profile. I have all the RGBxy and
>white point values custom set for the monitor. If I set it to Adobe RGB 1998
>don't I risk producing colors that I can't see or adjust on my monitor but
>will appear in a print?

Yes. But, there may also be colors you recorded, for instance on a chrome 
film, like velvia, that you captured on the film that you can reproduce 
with high end prints. If you convert the original image which contains 
these colors to a smaller color space that does not, you have thrown those 
colors away, and you will never be able to print them.




>2: My NEC monitor has an "sRGB" setting at 6500K which controls contrast and
>brightness as well as display colors. This setting appears somewhat flat,
>whites aren't crisp. It isn't what I would pick to view images or surf the
>web but it is supposed to be the best for color matching. Does any use or
>know more about this display option?

I don't know anything about the NEC monitor, but if you use sRGB as your 
working space in Photoshop, it should work.



>3: If I select the my scanner's Epson4870 profile as the Photoshop working
>space in the Photoshop color preferences all images look darker. I don't
>understand the point of having a profile for an input device, I thought it
>is just for matching the monitor image to output prints or images. What is
>the point of having a working space scanner profile? I am obviously missing
>something.


Do NOT use your scanner or monitor or printer as your working space!

For color management to work correctly, every device from input to output 
should be accurately described in a profile.

 From my book:

For example, a digital camera (or scanner) may take a picture of a color 
such as fire-engine red in a scene. The camera assigns a set of RGB pixel 
values to that color, say 250,0,0 that represent "fire-engine red" in the 
camera (or scanner) color space.

The camera (or scanner) then embeds a profile in the digital file that says 
(metaphorically) "The numbers 250,0,0 in this file should be interpreted to 
mean "fire-engine red" in the reference color space.

When the file is opened in Photoshop and viewed on a monitor, the Color 
Management System (CMS) looks at the numbers and their definitions in the 
camera color space and translates them into the reference color space, 
which is based on color as perceived by humans.

Then the CMS looks at the monitor profile and figures out what new numbers 
are necessary so that the display on the monitor will look like 
"fire-engine red". The CMS translates the numbers on the fly and sends them 
to the monitor.

Likewise, when output to a printer, the CMS looks at the printer's profile 
to see which particular numbers mean "fire-engine red" in that particular 
printer's color space, and the CMS translates the numbers from the original 
file's camera color space to different numbers to make the color match as 
closely as possible when output as a print.


Jerry 

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