Watercolour Test Works
The Standard Test Method for Raw Materials is used to prepare pigments in watercolour and oil to show up comparative levels of transparency, opacity and hue. The recipe and method are very simple (see below) and I have used it on all 35 of the colours collected from sites across the UK.
Six Bells raw ochre in gum arabic on paper
Tarn-y-garn raw ochre in gum arabic on paper
Cuthill raw ochre in gum arabic on paper
Caphouse raw ochre in gum arabic on paper
Saltburn raw ochre in gum arabic on paper
ColArt Standard Test Method For Raw Materials
Test Ref Number: Name of Test: Date and Status: Author:
Pigments - Graded Wash Issue 2 October 2001 Jivan Patel
Purpose: To assess raw material quality for colour in water based systems.
Equipment required: Analytical Balance, Automatic Muller, Palette Knife
Method: Accurately weigh out the pigment to be tested. The quantity for individual pigments can be found under Raw Material Test Methods file in Datasys Formulations systems. (100ml)
Transfer pigment to the automatic muller.
Add 2 mls. of gum solution for RM Testing to the pigment.
Mix to an even paste with the palette knife.
Lower the muller plate and run for 25 revolutions without weights, scraping down between each series of cycles.
Make a graded wash as per test ref. Number 8 in the Quality Control Test Methods Procedure manual.
Compare the graded wash with other washes from previous deliveries for colour variations