I don't have black fondant.. making an ipod cake.. if I paint with black gel color, will it streak alot ??? never done this before... thanks
Probably a little, but it depends on how large of an area you need to cover and how much you thin it. It's a good idea to mix your gel color with either vanilla extract (cheap stuff) or vodka...the alcohol will evaporate quickly and allow the paint to dry faster.
If you're just doing lines or lettering, you should be fine. I did my Zebra cake like that and it turned out perfectly.
If you're doing a large area and want an even colour, I'd suggest using Black Color Mist Spray by Wilton. It's easy to use and quite inexpensive.