Holograms in the Red Dwarf universe are characteristically marked with an "H" on their foreheads (with the exception of Ace Rimmer). There are hardlight holograms and softlight holograms. Hardlight holograms are almost indestructable and can only be turned off if they extract their own power source or the projection unit is switched off, they are effectively super humans.

Softlight holograms can be walked through and their power source can be extracted by anyone/thing, they cannot eat, drink or feel.