How to Mix Grays for Use with a limited Palette. by Don Finkeldei: This article describes how I premix warm and cool grays for use with my limited palette.
I mix my own grays from the primary colors. The grays vary in value and color temperature ( I mix both warm and cool grays). Premixed grays will result in finer control of the subtleties of value, color and chroma saturation needed in an oil painting. Another good reason to premix grays is once you start a painting it will proceed faster and you'll have less adjusting on the canvas. A good painter lays down a stroke of paint once and only needs to adjust edge softness or hardness. A master of single stroke painting is Richard Schmid. Mastering a "One stroke" method requires great skill. The use of gray moderators will help you get there much faster. Another artist that uses a limited palette with gray moderators is Scott Christensen.
Below are pictures of how I mix grays. Comments are included for each step. The mixed grays I make can vary greatly depending on the scene I'm painting, type of daylight (overcast or sunny day), reflected light and shadows. Note: The quality and consistency of paint you use is very important if you want predictable results each time you mix. Try to use paints from the same quality manufacturer. Don't use student grade or hues. I've found that the Utrecht brand is very consistent and doesn't vary in chroma saturation and pigment strength from tube to tube. I can hit the color temperature and value I want EXACTLY... every time.
In the first step I lay out a strip of cad orange (or cad red and cad yellow (same orange) and a strip of ultramarine blue. One part cad orange to 2.5 parts ultramarine. I also lay out two strips of titanium white that I'll use for mixing high value cool and warm grays. Since I'm using cadmium, white and ultramarine the grays mixed will be fairly opaque. If I need more transparent grays in my painting (lots of shadow areas where I may want a transparent wash) I'll use viridian and alizarin. See last image below for mixing transparent grays.
Next, I mix the orange and blue together to get a very dark (almost black) gray. That's the dark pile on the left created by mixing the orange and blue in the portions described above. Then, I take a little of the mixture and test the temperature with a little white. I want a flat neutral gray. If it's ok in color temperature I'll pull a little of the dark premix into the white and mix them. That will give me a very high value neutral gray I can use in skies or to knock down chroma in higher value passages. I then mix a "Khaki gray (warmer compared to the flat neutral gray) by adding a touch of yellow and a smaller touch of red. I want it about the same value as the high value neutral gray I mixed. The result is a high value set of warm and cool grays that can be used to moderate the primary colors, knock down chroma and adjust value.
I move the pools of grays to the top of the palette. Notice my primaries go from warm to cool from right to left. Cad red medium, cad yellow medium, cad lemon yellow, white as a main separator from warm to cool, and then ultramarine blue (cool compared to yellow and red)
To the left of the primaries I mix the grays. These are usually done from left to right getting higher in value and alternating warm and cool. I also mix a lower value cool and warm gray that's lower in value than the high value grays. The intermediate value of grays are not necessary but will give you another value range of grays to use when moderating your strong primaries up or down in value and and ajusting chroma intensity.
So, you can see I have the palette laid out from left to right in two sections. Grays on the left going from dark to light and alternating cool/warm. Primaries on the right of that going from cool to warm.
I now have a palette with gray moderators that I can use to quickly execute a painting with very fine control over hue, value, and chroma saturation. Learning how to use grays to moderate intensity and value of color will help you put one stroke down with confidence and know that it's right the first time. You'll do less "adjusting" things on your canvas (which can turn to mud if you fuss around too much, as you probably already know). You'll gain accuracy mixing the right paint you need for a mass or a stroke and you'll arrive at what you want much faster.
You can also mix a multitude of grays that you need for a specific painting. The grays above were mixed the same way using my base no-white neutral grays. I add white and extra pure pigment from the primaries (reds, yellows, blues) to get just the right mix for the hue, saturation and value I need for the painting I'm mixing for. Again, the primaries are on the upper right (red, two yellows and blue) and the grays are to the left of the primaries. Remember that grays can be warm or cool, high or low value, saturated or de-saturated. The definition of a gray is not a flat neutral gray without hue but any gray consisting of all three primaries. More of one primary than the the others still makes a gray -- but remember --all grays consist of all the primaries. Above I mixed green, yellow, red, purple, and neutral grays. You can buy grays similar to this but they will never match exactly what you want to accomplish or be the right value. Mixing your own paints will help develop the basic skill needed by all artists --- "How to Arrive at Exactly what you need", speed up the process of painting and allows you to complete it with a "One Stroke and Leave it Alone" technique.