This testing strategy for ceramic glazes is fast and effective. It can be used to test colorants—to explore increasing amounts of saturation—or to test base glaze additions in order to explore changes to a glaze or to correct problems.

I didn't invent this technique; it was used by chemists in an earlier age to investigate materials without weighing out tiny amounts.

The "Fast Five" is accurate enough to point to possible solutions with very little investment in time.

  • Weigh out 10 grams of a colorant or additive. Square and flatten the powder onto a piece of paper with a knife or spatula.
  • The Plan: With your knife, you will divide the 10 gram square in half and push the half to one side. Then you will divide one of the halves in half again, push it aside into a separate pile and repeat this four times, until you have 5 piles of the additive.
  • Push each pile aside as you divide it.
  • Beginning with the smallest pile, add it to 200 grams (100 dry) of a wet base glaze. Just assume that 200 wet grams equals 100 dry—it is close enough.
  • Stir the addition into the glaze and apply it to one end of a rectangular test tile (about 2 x 5 inches).
  • Continue to add the dry ingredient into the same cup of glaze, the smallest amount remaining each time. Remember to apply the glaze to the tile after each addition.
  • Label the back of the tile with glaze name and additive. You need not write the amounts on the tile as the percentages are always the same in a Fast Five test.