make 3D object lighter or darker

I think it would be great is it was possible to måle a 3d object on a layer lighter ør darker. Because if a draw a character on one bitmap layer and import the background set as an .obj and place it as a lager behind it would be nice to be able to måle the 3d object lighter so it is easier to see the character.

I really would be a great help if I easyly could lighten a 3D object (My Set). So I in a fast way could separate My characters draw on bitmap layers from the location which is a 3D object

Kind Regards Mads

I was just thinking why not also make this possible for 2D layers.
If we look at Toby Sheltons examples

We can see that he turns up and down the brightness of the layers to separate the different elements, so maybe it should be possible to add a FX to a layer that you can adjust. A blur would also be nice.
Just some thoughts