I was thinking about engraving, then color filling 4 12" absolute black tiles to put together in a 4' x 4' mosaic. On close inspection I can see small pits in both the marble and granite samples I have. I was wondering if the small pits would present much of a problem when color filling. I'm thinking the pits will hold the fill material and muddy up the background. I do know that others color fill this material and don't seem to be having a problem.