images in cross-platform stacks

[Phil Davis]

I just re-discovered something that might be helpful to others, so here 
goes.


Bottom line:
To simplify your code and your life, use JPG images, not PNGs, in stacks 
intended for cross-platform use. That way you don't have to mess with 
the screenGamma property to make everything look the same everywhere.


Situation:
I have a gray PNG file whose only color is 145,145,145 no matter what 
tool you use, Mac or PC, to get the color info.

Even from within OSX Rev, if the image file is opened in another app 
underneath Rev, I can use the color ppicker's magnifying glass to get 
the color - still 145,145,145.

Then I imported the image into a Rev stack. Boom! The color picker's 
magnifying glass now says the color in the Rev image object is 
123,123,123. What happened?

What happened was the screenGamma, since my image is a PNG file. Rev's 
screenGamma is a color? or brightness? or ??? adjustment factor applied 
only to PNG files. The screenGamma defaults are 1.7 for Mac and 2.2 for 
Windows. (I don't know what they are for Linux.)

I then used a graphics tool to convert it to JPG, and re-imported it 
into a Rev stack. The new image object's color is 145,145,145.

Cause identified!


HTH -
Phil Davis