[alt-photo] Re: color separations in Photoshop

[Mark Nelson]

Charles,

I'm going to make a wild guess and suggest that the problem lies in your working color space settings.  If you are converting to RGB using Adobe 1998 as your working color space, it has a native gamma of 2.2.  If your Grayscale working color space setting is something other than Grayscale Gamma 2.2, you are going to get a tonal shift just as you would if moving the Gray Pt Slider in Levels.  

I keep my Working Color Space Settings to Adobe 1998 & Grayscale 2.2 and there is no shift at all.

Good luck!

Best Wishes,
Mark Nelson

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On Nov 27, 2011, at 12:38 PM, Charles Ryberg wrote:

> Folks--In Photoshop when I have an image (RGB) and use the channels box to make separations the resulting files are Grayscale.  I can, of course, convert them to RGB.  My problem is that after I apply my curve there is a difference between the images left grayscale and those converted to RGB.
> 
>   Now, I derived the curves using the common 10 x 10 square which was, of course, in RGB --so it seems likely that I should convert.
> 
>   I don't remember seeing this discussed anywhere.
> 
>   Advise (yes, I'll try both ways if I need to).
> 
> Thanks    Charles     Portland Oregon 
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