Comment 10 for bug 171589

I was also thinking this too would be nice. What if you make a complete
drawing and later you noticed that the light areas are too light, or that
the entire picture is too dark, or that the blues are too green, or that
the reds are too bright?

In the new 0.45, there are some of these brightness and color controls,
but they are very inefficient. You should be able to use sliders and
equalizers.