Depends on specimen, depends on where in their molt cycle they are.Is it normal for different T's of the same species to have varying degrees of brightness in their colors? Or do they only show vibrancy once full grown?
This GBB looked jet black at RepticonDepends on specimen, depends on where in their molt cycle they are.
If you are comparing images on the net, then don't waste your time looking for the "right colors", there are tons of variables that go into digital imaging.
Also, don't forget about their natural iridescence. A single T can exhibit different colors depending upon the angle of light. A factor no one measures or notates in their photos.