OK, let’s do it step by step. What’s important is that you understand what’s happening.
- White balance.
White balance is important to eliminate color distortions produced by the camera itself. In this case this is the magenta (pink) which you can see well in windows. Although this is not so prominent in the other areas of the image, this color shift also affects the other colors, including the colors of the skin. So, let’s correct that first:
As you can see, I have selected a range in the window for whom I thought it should be white. Now you can see that the chairs and T-shirt of the girl look more natural.
- yellow color cast
Now it is a time to remove the yellow tint caused by the monochrome illumination. What is noticeable is that the brighter areas of the image are more affected by this than the darker ones.
So, if we want to remove the color cast, we have to take that into account.
The B channel of the LAB color curve is very suitable for this. First we have to find out which area we shouldn’t influence too much. This is, for example, the area of the woman’s face. Therefore we take color picker (area) and look where this area is in the B channel.
This will be our " break point " for the curve:
Now we remove the yellow cast by making a bend on the marked place in the curve, and make sure that the wall does not become too bluish.
This is a bit tricky here but the reference next to the face is also the light area of the wall to the left of the window. It should remain white as far as possible:
- Increasing color saturation with Velvia
Since the yellow tint has suppressed the other colors, the color saturation must be increased to see what else needs to be done:
- further color correction
As you can see, the facial colors are slowly appearing, but the yellow cast is not completely gone yet. We now repeat the process with the curve, this time with parametric mask to protect the face colors even more:
- brightening the image
At the end, we take another color curve to brighten the picture:
The whole thing is of course very tricky, and each time you get a little different outcome, but still, with a bit of patience you can get very satisfying results.