There are two types of C4Ds: effect C4Ds and the other kind

. Effect C4Ds will be in a black background and are usually shiny and flashy. I am guessing these are what you are talking about. Just put the layer to screen, linear dodge, color dodge, or lighten depending on what looks best. Then apply a layer mask and erase with your brush set to black whatever doesn't look good. Try to place the C4D in the direction of the general flow of the signature. In other words, you don't want bits of it sticking out in random directions.
A render is an image cut out of the background, so yes, you cut it out. It does take a while to do, so if you're feeling lazy, head on over to www.planetrenders.net. Simply register, and search for a render you like. They also have C4D and abstract renders.
This post was edited by SaffasMissionary on Aug 21 2008 02:42pm