Day-of-the-Dead Mosaic Grouted

Black Grout vs White Grout

Black grouts bring out the intensity of tile colors while white grouts overwhelm them. Natalie Knox’s Day of the Dead Skull mosaic is a good example of how well black grouts work and how a light colored backer isn’t a good indicator of the mosaic would look with white grout.

Don’t Be Fooled

If you lay the mosaic out on a white backer and try to use that as an indication of what the mosaic will look like with white grout, remember this:

When the gaps are filled with grout, they won’t have all the contrast provided by empty gaps, which have depth and shadow. A lot of white concrete at the same level as the surface of the glass tends to make the colors look washed out.

Day-of-the-Dead Mosaic ungrouted
Day-of-the-Dead Mosaic by Natalie Knox in process before grouting.

Looks Can Deceive

The photo above does NOT give an accurate impression of what the skull would look like grouted with white grout compared to black grout for several reasons.

  • The empty gaps have a lot of depth and shadow because the light source is bright and to the side.
  • There is additional contrast (compared to the photo of the black-grouted mosaic) because the dark background shows through the many slits in the mouth and eyes.
  • The ungrouted mosaic was photographed in warmer light. Imagine it in cooler saturated light like the light in the photo of the grouted mosaic.
  • The backer isn’t white. It is the warm hay color of unfinished plywood. If you are set on using white, use an off white, never pure white.

Tip: Antique Whites and Light Beiges and Eggshells and Cremes and other similar light hues make better “whites” than pure white grout when used in mosaic images.

Making White Grout Work

Skulls are white, and so in this case a white grout makes sense in terms of what was being rendered. That still doesn’t change the fact that there will be a loss of contrast and the other issues explained above.

This particular mosaic could get away with white grout because the grout gaps are relatively small. The smaller the grout gap, the less flash of bright white the overall image will have scattered throughout.

If larger grout gaps are used, the mosaic image is dominated by lines of white concrete not the tile, and you find yourself wishing you had made the tiles larger. I think that would still be the case even if there is supposed to be skull or painted white face under the tile.

Tip for minimizing the visual impact of grouting:

Grouting changes the look of a mosaic, and many novices are disappointed because they used large grout gaps. To minimize the visual impact of grouting (and the choice of grout color), keep your grout gap minimal.

Tip for minimizing grout gaps:

If tiles only touch at points but not along the length of their sides, then tiles can be positioned very closely and yet still be grouted. Consider working in this way instead of carefully cutting each tile to maintain a uniform grout gap.






13 responses to “Black Grout vs White Grout”

  1. Jan Howard Avatar
    Jan Howard

    Can you regrout over white grout? I am disappointed in my project using seaglass and wished I hadn’t grouted at all. They are very large mirrors so starting over isn’t an option. But would using black grout over the existing white grout work and give the richness of the seaglass color back? Also I used sanded grout which may have dulled the blue and green colors. Should I have used nonsanded?

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Jan,

      No, nonsanded grout is only used for hairline cracks (or mixing with sand). The sand didn’t dull the beach glass. That is grout residue. You can remove it by wiping with vinegar, but you have to wash it off quickly and thoroughly to avoid dissolving or bleaching the grout.

      You can’t regrout without scraping out the old grout. You can use artists acrylic paint to “stain” grout for dry indoor mosaics. The paint should stick to the porous grout but wipe cleanly off the glass.

      I hope this helps!

      1. Jan Howard Avatar
        Jan Howard

        Thank you so much for your suggestions. Will give it a try!

  2. Tephillah Avatar

    Hi Joe,
    I have same problem too, I used dark grey grout the blue sky. But the grout made the sky colour look so dull. Is it use white grout better?

    1. Joe Moorman Avatar
      Joe Moorman

      Pure white ruins mosaics for the most part. Gray may have been a mistake, but white might have been a bigger mistake. Find a contrasting color, but avoid pure white. Perhaps and off-white.

      1. Keli Avatar

        Hi Joe, for the person who used dark grey for the blue sky,I heard tan should be used for blues? So if I wanted to use a light grout (like tan) with other areas of my mosaic with grey, how would I proceed?

        1. Joe Moorman Avatar
          Joe Moorman

          There isn’t one recommended color grout for a particular color tile. You are probably better off with a gray for a blue sky than a tan that might contrast too much. The ideal color for the sky is probably a gray that contrasts enough. The situations to be avoided are: 1. a gray that is so light it doesn’t contrast tile color, and 2. a tan so intense it doesn’t look right in the sky.

  3. Anne Avatar

    Hi Joe
    My mosaic is a woman’s face looking up at the night sky. What color grout is best for this?


    1. Joe Moorman Avatar
      Joe Moorman

      It depends on the colors used in the mosaic.

      1. Anne Avatar

        The woman’s face has light pinks and the sky is dark blues. Should I use a dark grout or light grout?


  4. Ray Avatar

    I made a glass cupcake with bright, hot pink “frosting” and purple and silver base. I planned on black grout for more of a punk look but I’m wondering if white might be better. I’ve only used white grout for a sculpture once and it looked terrible, so I’m very hesitant. Do you have any advice? Thank you so much for your expertise!

  5. Gloria hurwitz Avatar
    Gloria hurwitz

    I used a dark blue grout. However it is so similar to the color of the tesserae that the design is lost. The tesserae is mostly dark blue and white. I want to use acrylic to change grout color . What color would you recommend?

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Gloria,

      Please email us a picture of the mosaic, and I will take a look.

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