Proof Colors Setup in PS3

[Mike Sellers]

What is the purpose of the Preserve RGB Numbers check box in Proof Setup? When checked it makes a radical change to the colors.
Mike

[Jalok]

I do not know if people make other profits from this feature, but I use it to evaluate the profile strain to reproduce a given color, comparing how much different hue and saturation are from the real color. 

[digitaldog]

Preserve Colors shows you what that document would output like if you did NOT use an output profile.

Useful for CMYK workflows (what would this CMYK data look like if I send it to a differing press without a conversion). Not useful for RGB workflows unless you want to illustrate how ugly an image would print, going through a color management path without the profile.