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Can I make changes to black-grey-white areas only?

Apr 6, 2014, 18:26
Post: #1
Can I make changes to black-grey-white areas only?
Eventually I want to make a script fu script so I can't just use fuzzy select tool or select by color. Basically I want to change the color curves for areas which are gray-scale, and leave alone anything colorful (red, blue, purple orange...) Is that possible?

If I could do it with a selection it would be even better because I might want to do the opposite later.
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Apr 8, 2014, 09:51 (This post was last modified: Apr 8, 2014 09:55 by rich2005.)
Post: #2
RE: Can I make changes to black-grey-white areas only?
I was thinking along the lines of this.

An image with a mix of colour and gray in it.
[Image: SpgOYth.jpg]

Decompose to CMYK and use the K channel as a layer mask on a duplicated layer
[Image: 1exziSk.jpg]

Then tweak that duplicated layer to adjust the gray bit.
[Image: vApJfhc.jpg]

Don't know how you would script it though.

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