You will want to de-emphasize and subdue certain areas of your painting allowing your focal objects and areas to take precedence. Another reason: using grays to moderate the primaries allows you to build a reserve into your painting and creates harmony.
The reason is that a scene in nature almost never contains pure primary colors either. I almost never use pure primary tube colors on the canvas directly. An intense chroma of purple ( in this case ) is lessened by graying the purple (making the chroma less intense) and the value (lightness/darkness) is modified by either using a darker or lighter value of neutral gray (lighter values have more white in the gray, darker values have less white in the gray). You can then use the neutral grays (of the right value you need) mixed with the purple to attain the correct chroma (color intensity) and not have to worry about changing the color. As an example, lets say you mix pure red and blue together to get a purple color (hue). Using neutral grays to adjust chroma and value without modifying the hue is obviously an advantage with this technique and will give you much greater control in mixing paints. Value is the lightness or darkness of the paint as seen without color (gray scale - what it would be if on a scale of black to white). Pure primary colors (cadmium red, Cadmium yellow or ultramarine blue) have maximum chroma. They are hue (color), value (lightness or darkness as viewed with no chroma - grays) and chroma (color intensity). There are three properties of any paint you use. Sometimes I mix three or more value ranges (darker to lighter) of cool and warm grays, especially if a painting will contain primarily shadow areas where I want fine control over the color intensity and values in the shadows. I mix a lighter cool gray by adding white and blue to the dark gray and a lighter warm gray by adding white, yellow and red (a khaki gray color). This combination makes a very dark neutral gray ( that I’ll use to mix the darkest shadow colors for the painting).
You can also use orange since that's the same as equal parts of yellow and red. I mix a very dark gray (almost black) by using 2.5 parts of ultramarine blue, 1 part cadmium red light and 1 part cadmium yellow medium (I use Utrecht paints, other brands might require different parts). Rather than adjusting the tube colors with complementary colors and white to decrease intensity and adjust value, I use grays that I pre-mix to moderate the tube colors. I use a limited palette (cadmium red light, cadmium yellow medium, cadmium lemon yellow, ultramarine blue and a little Alizarin and viridian).
#Paintingnails using just gray with artmatic how to#
By Don Finkeldei: How to achieve harmony, balance and reserve in your oil painting by pre-mixing grays from the primary colors.