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+--- Thread: Remove selective cast/stain (/Thread-Remove-selective-cast-stain)
Remove selective cast/stain - The_JinJ - 06-29-2017
Hi all
I'm looking for ways to remove selective areas of red stain/cast on an image.
I can remove an overall red cast using inverted average colour but short of converting to B&W (using the undamaged red channel) and recolouring or cloning areas I can't figure out a way to do this.
A thought was using channels somehow, maybe as a mask, as the red channel has no damage, green and blue do.
Here's an image with the general red cast removed on the left and the remaining stains on the right.
![[Image: iyf5njyl.png]](http://i.imgur.com/iyf5njyl.png)
Any help appreciated!
RE: Remove selective cast/stain - rich2005 - 06-29-2017
Tried a few things with little success.
You might have to bite-the-bullet, go 'artistic' and recolorise.
Using gmic plugin http://www.gmic.eu
desaturate, a little touch up
paint in a colour map
apply
![[Image: 44CqJHn.jpg]](http://i.imgur.com/44CqJHn.jpg)
RE: Remove selective cast/stain - The_JinJ - 06-29-2017
Good try that...I can't seem to get the filter to work - I have a B&W image as bottom layer and a colored top layer but not merging the two..... any ideas?
I tried wavelet decompose and tidied up the colour residual image with some success.
RE: Remove selective cast/stain - rich2005 - 06-29-2017
(06-29-2017, 04:50 PM)The_JinJ Wrote: Good try that...I can't seem to get the filter to work - I have a B&W image as bottom layer and a colored top layer but not merging the two..... any ideas?
I tried wavelet decompose and tidied up the colour residual image with some success.
Not something I use very often, so I usually have to fiddle around with it.
Although it says B & W the image obviously has to be in RGB mode.
then it is set up like this: http://i.imgur.com/rLhrbI8.jpg - all layers - bottom (desaturated) layer active - output to a new file.
RE: Remove selective cast/stain - The_JinJ - 06-29-2017
(06-29-2017, 06:01 PM)rich2005 Wrote:(06-29-2017, 04:50 PM)The_JinJ Wrote: Good try that...I can't seem to get the filter to work - I have a B&W image as bottom layer and a colored top layer but not merging the two..... any ideas?
I tried wavelet decompose and tidied up the colour residual image with some success.
Not something I use very often, so I usually have to fiddle around with it.
Although it says B & W the image obviously has to be in RGB mode.
then it is set up like this: http://i.imgur.com/rLhrbI8.jpg - all layers - bottom (desaturated) layer active - output to a new file.
Thanks! I had the input layers set incorrectly, obvious mistake
RE: Remove selective cast/stain - grits - 07-03-2017
I did not use G'MIC. In gimp, colors > components > decompose. Choose the red layer. Change Image > mode to RGB.
Then I painted on a new layer, as above, and set it to mode- Color, Opacity- 65%.
Decompose made a perfect monochrome layer to work with.
I used the original image, above, the image on the right, but you could probably get better highlights with the one on the left.
I could of done a better job of painting, I know.
RE: Remove selective cast/stain - The_JinJ - 07-03-2017
Nice!
That's how I ended up doing it, using red channel and ultimately repainting....
Wavelet Decompose was also interesting where you clone colour on the residual layer and smudge to blend.
(07-03-2017, 07:44 PM)grits Wrote: I did not use G'MIC. In gimp, colors > components > decompose. Choose the red layer. Change Image > mode to RGB.
Then I painted on a new layer, as above, and set it to mode- Color, Opacity- 65%.
Decompose made a perfect monochrome layer to work with.
I used the original image, above, the image on the right, but you could probably get better highlights with the one on the left.
I could of done a better job of painting, I know.