Screen gamma and PNG files

[Howard Bornstein]

I'm back to this issue I dealt with a couple of years ago--getting
images to look the same across platforms.

The problem was that images would look different on different
platforms because the screen gamma for each platform was different--
1.8 on Macs and 2.2 on Windows. I'd create art in Photoshop (with it's
default set to 1.8) and when I display it within Rev on Windows, it's
way lighter than what I saw.

So, one solution was to set the default in PS to 2.2 so I would know
in advance how this would look.

First question: I can't find any way to set this default in PhotoShop
CS (for the Mac) like I did in PS 5.5. Anybody know where this is
done?

Secondly, it seemed that since I can detect the platform I'm running
on, and since I can set the screen gamma within Rev (using the
screengamma command) that I could determine the platform and then set
the screen gamma accordingly. I could even force the graphics (as long
as they were PNGs) to correspond to the set gamma.

>From the user docs:

Tip:  To force Revolution to re-decompress a PNG image without leaving
the card, put the image into itself:

set the screenGamma to 2.2
put image "Test PNG" into image "Test PNG"

So I thought I'd try this. I set up a little stack with a png image
and a button that would reset the gamma and re-decompress the image.
To my surprise, no matter what I set the screen gamma to, the image
disappeared!

Does anyone have a clue why this happened? Am I incorrect in my
assumption that I should be able to set the screen gamma according to
platform and that this should work? How are other people handling this
issue?

-- 
Regards,

Howard Bornstein
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www.designeq.com