Remove selective cast/stain

[The_JinJ]

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.



Any help appreciated!

[rich2005]

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

[The_JinJ]

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.

[rich2005]

(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.

[The_JinJ]

(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

[grits]

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.

[The_JinJ]

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.