Here are some link to resources and that people might find useful. 

Ruth Siddall’s Recipes

Slade School Pigment Farm Talks 

Over the Spring we had a series of lockdown talks to celebrate the Pigment Farm Project; the talks were about dyes, lake pigments and plants in art generally and come from Emma Richardson, Ruth Siddall, Nicholas Laessing, Andreea Ionascu and Lea Collet. You can watch the recordings of the talks here.

Slade Methods Room Recipes

Lots of pdfs with recipes and methods for making a range of artists materials and other constructions.