jeffrey_castleman's profile

3 Messages

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102 Points

Fri, Mar 17, 2017 6:39 AM

Decontaminate color feature causing strange artifacts in edge detection radius

I would like to start by saying that I am mostly very pleased with the new select and mask feature. I mostly shoot in a studio, and have been able to make extremely detailed selections of hair that would not have been possible before. 

My question is: why is the decontaminate color feature causing strange artifacts on the edge of the mask?

I think it has something to do with the edge detection radius, but that's just a guess based on the size and placement of the artifacts, which seem to match where the edge detection radius would cover. When I output the selection/mask it looks great, but when I try to paint parts of the original image back in, strange artifacts are revealed.

I'm including a picture of what happens when I paint white into a mask that has been created using the decontaminate color feature of the select and mask dialogue. 

How can I use the decontaminate color feature without this happening?

Thank you,
--Jeff

608 Messages

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13.1K Points

5 y ago

Thanks for posting this Jeff. I have the same issue, I just don't use the decontaminate color feature anymore because of this. I actually thought it was because I wasn't doing something correctly but it's good to know that it is happening to someone else as well so it's not just my imagination. :)

189 Messages

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4K Points

5 y ago

What you see is no bug, it ́s the way decontamination works. It automatically "paints" colors over the edges of your object. Of course, revealing that decontamination by painting into the mask, shows what the decontamination actually did. You ́re simply not supposed to paint into your mask after decontamination.

189 Messages

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4K Points

5 y ago

BTW. if you already have a mask (and not yet done any decontamination), you can do decontamination afterwards:
Go to "Layer>matting>decontaminate colors"
or
just go into "Select and Mask" again and do nothing but check decontamination.

3 Messages

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102 Points

5 y ago

Stefan,

My students and I thank you tremendously for explaining this! And thanks for the tip on how to decontaminate colors outside of the select and mask dialogue--exactly what I was looking for! Thank you!

--Jeff

189 Messages

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4K Points

5 y ago

You ́re welcome, Jeff!