Practical color mixing 3: chroma

This is the third post on mix­ing color. The first was about value and the sec­ond was about hue. Now it’s time to talk about chroma.

Iden­ti­fy­ing chroma

As with value and hue, the best way to iden­tify chroma is in terms of rela­tion­ships. How intense is the color you’re look­ing at com­pared with the inten­sity of other col­ors around it? Chroma can be hard to sep­a­rate out from value; light col­ors some­times look more intense than they are, and dark col­ors some­times look less intense. You get bet­ter with practice.

Bad chroma!

Enough with those bright orange skin tones already!

Work­ing with low-chroma color

Almost all paints are high in chroma right out of the tube. Since most of the world is low in chroma, the major­ity of a real­is­tic paint­ing will con­sist of neu­trals and near-neutrals. So a real­ist painter is going to have to spend a lot of mix­ing time reduc­ing the chroma of paint.

Reduc­ing chroma with mix­ing complements

Other than yel­low and vio­let, it is very help­ful to exper­i­ment with, and mem­o­rize, pairs of com­ple­men­tary col­ors. As a gen­eral rule, if you want to dull down an intense color, choose a dull com­ple­ment. Blues have mix­ing com­ple­ments in the range of warm yel­lows, oranges, and mid­dle reds. Mid­dle and cool greens have mix­ing com­ple­ments in the range from mid­dle reds to vio­lets. Warm greens have mix­ing com­ple­ments among the vio­lets. Some of my favorite mix­ing com­ple­ments include raw sienna/ultramarine blue, viridian/pyrol ruby, Pruss­ian blue/Venetian red, and ultra­ma­rine blue/raw umber. I expect that most artists develop a set of strongly pre­ferred mix­ing complements.

Reduc­ing chroma with opti­cal color mixing

Reduc­ing chroma with white

Reduc­ing chroma with grey

Reduc­ing chroma with glazing

If you paint one color thinly over another color, you get an opti­cal mix­ture. Blue glazed over yel­low pro­duces a green, for exam­ple. You can use this effect to reduce chroma, since an opti­cal mix­ture is darker and duller than the col­ors that make it up. Michelan­gelo, for exam­ple, some­times made a dark dull blue by glaz­ing ultra­ma­rine over black.

The browns and the brown-ish

Work­ing with high-chroma color

OK,

Simul­ta­ne­ous contrast

Because of the way the visual sys­tem works, a color is per­ceived as more chro­matic when it is placed next to its visual com­ple­ment. The impres­sion­ists made fre­quent use of this prin­ci­ple. A bright magenta looks more intense when it is sur­rounded by a dull green. The com­ple­ments iden­ti­fied in the Mun­sell color sys­tem more accu­rately reflect human color vision than those in the anti­quated three pri­mary color wheel.

Mas­stone and undertone

self por­trait

Main­tain­ing chroma at high values

Main­tain­ing chroma by glazing

One effec­tive way to main­tain chroma is by glaz­ing. If you apply paint very thinly over white, you can get a higher chroma than you could by mix­ing that paint to the same value using white. And a trans­par­ent paint that is applied a lit­tle more thickly can be more chro­matic at low val­ues than you might be able to obtain with a mix­ture of the same hue.