You can't see the difference between black and red? I'm colourblind and I have no such trouble, it's quite unusual. Apparently it can occur with Protanopia, but usually only when the red is particularly dark. Protanopia is red-green colourblindness but with the light deficiency you describe. I have Deuteranopia, which is just red-green colourblindness.
*Cough* er... was that off-topic? ;-)