Hi Leslie- actually, that pigment was added by archeologists to make the etchings more easily visible (currently the pigment is being removed from all od them to make them more authentic - though they will be much harder to see! Weirding enough, the originals were more visible because the rocks has a rust-red coat on them. So the etching appeared white against red. That coating has faded, which is why the 'restored ones are white-white now.