I'd need to see more the setup you may be using but it you're using the Auto settings on a black subject the camera thinks that it needs to open up and let more light in. That would wash out or blow out your image. Try using manual mode and adjusting from there. Set the camera up and make an frame using what the camera light meter says is good. Evaluate that and then close the lens down allowing less light into the camera. That being said, what is the background like is it on a table with light fabric or paper under and around? You really just need to try out multiple set ups to see what will work given your situation. That's about all I can say at the moment. I'm sure others will have more thoughts later. Just remember not to rely on the Auto modes on the cameras they aren't always correct.
Could you post a photo showing an example of what you've been getting? That would help with helping you out maybe.
Shooterscott
QUOTE (lowracer @ December 5th 2009 5:35 PM)

Title says it all. When I photograph my AR, which is black as coal when I look at it, the photo shows it as a light-medium gray. For the record I have a Canon EOS 5D, tried various settings including fully automatic and I'm using a bounce flash or natural daylight coming in at an angle.