Color

I have noticed that Banksy does use some color in his work, sometimes in the entire picture, but mostly on some parts of the body or clothing. To me it seems that some of these examples help to define where the arms are when it goes across the body and wouldn't normally be seen due to shadows if it was only black and white. This is something I can use if I have problems with the different elements in the picture, for example if a rifle makes an arm look non existant and the girl in the picture seem to be oddly shaped or missing limbs.