Grading uv map

When I ad a Uv map on an object, it does not blend with the other colors because they are form to different sources. Could I change the color in Blender or do I have to do it in my image editor?

I 'm not sure what you mean… If you mean “retouching” a texture so that the tone matches another image, then you 'd better correct it in another image editor…
I guess you could use nodes but i don’t see the proffit here.

Can you be more precise ?

I think that’s what I meant. Thanks