The Grass is Always Browner

If you Google Reticulated Glazes a small explanation of Lichens, Lizards and Leopards Oh My! Reticulated Glaze Recipes for Wild Ceramic Surfaces by Robin " Grass" Hopper will be first on the list in the Ceramic Arts Daily blog. There is only one colour worse than brown and that is shiny brown. Although my favourite time to look at pots is when they are wet I sure don't want to see shiny brown. There is a mistake in the Ceramic Arts Daily article. Just as I have done here they suggest a black slip under the reticulated glaze so that when it peels back you see black and not the boring colour of my clay body.
The slip they give is from Grass's book The Ceramic Spectrum from Page 210. They have forgotten to list the oxide colourants to turn this muddy slip into a black one.
Here is the slip from the book.
Black Slip
35 Ball Clay
45 Barnard Clay
10 Feldspar
10 Silica
Add: 2% each of cobalt, copper, iron and manganese.
The article in Ceramic Arts Daily is meant to be a teaser and it is! If you want the full monty buy the book.