A scale of nine value steps made by mixing Titanium White with Ivory Black produces cool grays with a slight blue bias. A scale of nine value steps made by mixing Titanium White with Raw Umber produces warm grays with a yellow bias. "Neutral Gray" can be arrived at by mixing the cool gray with the warm gray at each of their nine value steps. The full range of neutral values includes both extremes white and black. White is designated value #10, black is value #0 and between them are values #9 through #1, comprising the eleven-step scale of Neutrals. Your judgement of true "Neutral" (with minimal spectrum bias) might best be determined under a north-light source.
The Neutrals can also be used to control the chroma of any color without altering its hue. (Mr. Reilly preferred the specific term Neutral to mean a pigment that has no hue bias, while the casual term "gray" can imply very weak chroma of any hue). Oil paint comes out of the tube often at it's most chromatic. These neutrals can be used to reduce the chroma without changing the hue. For example, if your goal is to make a middle value muted purple (P5/6), you might take Dioxazine purple (P1/12), add white to bring it to value 5, then add Neutral 5 until it's chroma is weakened sufficiently.
In the late '40s, Reilly contracted Grumbacher to mix and tube boxed-sets of all nine Reilly Neutral values. Sadly they are no longer available. Tubing your own Neutrals saves time and promotes palette consistency. Empty tubes are available at art material suppliers like Pearl Paint and Utrecht.
|Photo courtesy of Jerry Allison|
Mixing the neutrals.
Using Ivory Black and Titanium White, mix nine intermediate piles of paint from dark to light. Black representing the value #0 and white representing value #10, the neutral colors will be values 1 through 9. Including black and white you will have eleven equidistant values. Next create a separate string of nine corresponding values mixing Raw Umber with Titanium White. Now, relying on your own judgement, blend these two strings together visually until they appear to be completely neutral in hue.
Jack Faragasso's 1979 book is a good reference for paint mixing.
For your bookshelp: The Student's Guide to PAINTING by Jack Faragasso
Next Topic: The Reilly Palette: A Palette of Convenience
© John Ennis 2010