bright reds can be problematic in video… what is your destination for this piece… web/computer or video?
if it is video, you have two choices… you can make a broadcast safe color level adjustment in ae by creating an adjustmnet layer at the top of your comp, then add levels and set the black output to 16 and the white output to 235. or if you are taking the piece into an nle, you can import the file as rgb and have the nle convert it to yuv color space. if you do the latter, you will need to work witha codec that gives you better color, like losseless or perhaps a png image sequence, to maintain the color as well as possible.
if you are outputing for web/computer dispay, then you may want to work again with a better codec as mentioned above, and use a compression tool, like sorenson squeeze, to create the compressed file. compression software will almost always give you better quality and smaller files than just rendering out of ae. they have the advantage of being able to look at all the frames and base compression on the whole piece rather than frame by frame as each gets rendered.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW