Anna Calluori Holcombe
Pottery Making Illustrated,
Spring 1999, page 12

In the same article are two of Richard Zakin’s Terra Sigillata Recipes.

RedArt ..................................................... 1000 grams
Calgon Water Softener................... 5 grams
Water........................................................ 2500 grams

This will make a red terra sigillata, good for mixing darker colors.

GoldArt.................................................... 1000 grams
Calgon Water Softener ..................5 grams
Water .......................................................2000 grams

This will make a white terra sigillata, which is good for lighter colors.

Add about a teaspoon of (Mason) stain to an 8-oz. cup of terra sigillata as a standard measure and then add more or less for the shade of color desired.