As expected, black was painfully slow to dry. In this test, we included:
- bone black (4 days)
- bone black slightly gritty (8 days with very apparent tack)
- black Roman earth (4 days with some tack)
The drying times of the specialty colors:
- vermilion – 21 hours- but color rubs off slightly
- azurite – 22 hours
- lapis – 44 hours
- minium – 44 hours
Eight green earths were tested and found to have wildly different drying times. Celadonite was the slowest of all the tested colors, including the blacks.
The careful record keeping and precise testing was splendidly beneficial. After review of the results, I have eliminated many colors and now have 16 reasonably fast drying pigments plus white for my palette. I now use: 1 each, green earth, red, blue, blue/green, red.orange, 2 umbers, 4 ochres, 4 siennas, and 1 black. Sometimes I sneak in a little lead-tin-yellow and a few lakes which beautifully round out all that is necessary.
This simple limited palette is remarkably varied. I can achieve an endless range of bright, subtle, dark, light and neutral tones.