are they real cement tiles or porcelain?
if cement, seal them first before grouting. if doing a dark color, pipe in the grout carefully and don't smear it all over the tiles. do a few tiles at a time, and quickly wipe off excess. (I can't stress enough to seal them very well before grouting)
if they're porcelain or ceramic, they're fine to do a dark color and grout like any other tile.
I did a black w/mine (they are cement. i had to be very careful and not let the black grout get on the white portion. yes I sealed them 4 times prior to grouting!
White on a bathroom floor will get dirty a lot quicker.
the other option is to do a medium gray. gray visually disappears. pick a neutral gray, neither blue or beige.
this is Custom Polyblend.
look at Natural Gray, Platinum, Charcoal or bright white. (just know that the white will get dingy w/use)
Mapei colors. Charcoal, Black, Pearl gray, Silver or White. I used this grout w/mine
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grout colors
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