It's not free ($179 for single licenses, $120 for 2+), but you may want to look into the
Sheer Codec. This is a proven codec used on The Simpsons and other high profile projects.
If you want to avoid buying codecs, you may want to consider using image sequences such as TGA or even TIFF, although I'm not sure how well Color handles LZW or other lossless image schemes.
Brendan Coots
Splitvision Digital
www.splitvisiondigital.com