Question about masks

This is the Discussion Board for the March 2010 CM101 Class.
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Joined: Thu Sep 04, 2008 1:07 pm

Postby kessi » Mon Apr 12, 2010 5:08 am

Hi Greg,
I have been struggling with the mask assignment on Sun Moon Harbor. When I use the K channel to create the mask what curve channel do I use. Can I use the a or lightness channel from Lab or must I use the curves from CMYK?

I also had problems with the inverting of the K channel mask and upgraded from CM version 3.012 to ver 3.018. This crashed Photoshop Elements 6 so I went back to version 3.012.
I can invert the mask now. I probably just did the wrong thing initially.


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Postby ggroess » Mon Apr 12, 2010 7:00 pm

In the Sun Moon Harbor image...
The Channel mask is just that a mask.  You can take the mask from K in CMYK or from R in RGB.  You can even use the L channel in LAB.  It matters not what color space you want to make your corrections in. 

Once you have made the mask, switch color spaces; the mask should stay put.  If you are copying the K channel to the clipboard to add to a layer in PS or Elements; there is a known issue with the K channel copy.  The L channel should allow you to accomplish what you want to do if you are doing that. 

This really is a short cut for a much more difficult PS or PSE process.  You can take the channel from a copy of the image in PS and adjust the channel into a mask;  then copy it back to the image as a layer mask.  It really has a large amount of steps when compared to the CM.


Posts: 210
Joined: Thu Sep 04, 2008 1:07 pm

Postby kessi » Tue Apr 13, 2010 5:26 am

The proverbial light went on.
Thanks, Greg.


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