Negating a Color Filter

[nicknack]

This is probably a really simple fix, but I'm still a beginner at photo manipulation.

 

If I have a picture that is partly distorted by a color filter, is there any way I can negate the color distortion?

 

For example, if I had a picture like this:

 

 

where I can use the sky or grass or bricks as reference points, how would I cancel out the color and make the whole picture look normal?

 

[pdnnoob]

It sounds like a simple problem, but it's a lot harder than you might think.

The problem is that, when the color filter was used, the color in the original image was "replaced" with the color chosen for the filter. There isn't, programmatically, a way to know what the original color was.

[nicknack]

That's true, but you can assume that the color filter is consistant, right? So could you, pick a small patch of sky next to where the filter overlaps. The sky color is fairly consistant, so then you would have what the true color is, and what the color looks like under the filter. Is there any way to use that to figure out the color of the filter by itself, then somehow remove that from the image?

[pdnnoob]

The change wasn't uniform over the entire image. Otherwise, it would be a simple hue change and you would have a variety of colors in the filtered section. The filter made the image black and white, and used the color as "gray". That means there is no way to know for sure what the colors were previously. The only thing you know from a programming standpoint is the brightness.

In short, undoing the filter cannot be done with a simple click of a button. You'll have to figure out some way to do it manually.

[Ego Eram Reputo]

Very roughly:

I saved panel two as a separate image so I could use its palette later on with this plugin: Color Match

Then I desaturated the image to (very roughly) equalize the color information.

Finally I applied the palette from panel two image n order to get this:

You can see that the image is only very slightly colored. It's going to take a significant amount of work to get it looking acceptable.