It looks to me like they locked the transparent pixels on the line art layer (which contains all of the solid blacks including the one guy's hair) and used a light brown/orange gradient on it. I say this because if you look very carefully, none of the coloured parts are actually affected by this. I do a lot of this when I CG--it's useful for other effects as well.
I've actually got to go against this <<'. Locking opacity layers is a fantastic tool but after sampling colors from the image it seems(hard to say for sure with all the compression artifacts getting in the way) that the skin color tones trend towards being lighter as they get closer to the bloom. That is to say, it appears as if they just dabbed right over the image with a low opacity, low hardness brush.

I got the above right image by touching the screen with a brush at 30% opacity and 20% hardness with the lighting color I wanted.