"Colour and I are one. I am a painter."
Paul Klee, 1914. Reference.
Brian McGurgan's color thumbs for our Abandoned Barn Project diverge quite well from my own. He had an early goal of working with neutrals and browns, and I salute his idea of having a color theory from the very beginning of a project. It's always best to have a color plan, or else the colors may get away from you and you'll wander aimlessly trying to resolve your color composition.
Let's review our browns. I think of Umber, Sienna, and Ochre when I think of brown. See a list of browns here. I omit Sepia, which is derived from the ink sac of the Cuttlefish, rather than from minerals. The family of browns based around iron oxides is called earth pigments.
When my mother washed my diapers in a river fed by iron springs, they took on a red color.
Umber, with it's iron oxide component, may have a red field to it. When my mother washed my diapers in a river fed by iron springs, they took on a red color. Vermeer liked his Umber. One may find an Umber with a green cast, however.
Here is the yellow opinion of Burnt Umber. Confused? Maybe the Real Color Wheel people in that link take a systems approach to color. Otherwise one takes the pigment source of the color and arrives at Umber, which is reddened by iron and manganese.
Divide your Siennas into the Burnt Sienna (red) and the Raw Sienna (yellow) categories. Van Gogh valued Sienna.
Ochre is a light yellow brown and probably my favorite of the earth colors. Etymology: ὠχρός (Greek for yellow). I also favor the Brown Ochre made from Goethite, originally used at Lascaux.
Olives are seen by many to be in the brown category, but I arrange mine with the rest of my greens.
Did you know that browns have compliments, too?
Did you know that browns have compliments, too? I have my browns divided very basically into two sections in my palette, those with a yellow field and those more reddish. If you were to put an undertoned ground of green beneath your red-field browns a "pop" will occur. In other words, I would tell Brian in this phase of our project to think about sets of colors or relationships when approaching color ideas for this painting. I often think of a triadic relationship, like red, violet and blue or violet, yellow and green. Perhaps, for these neutral compositions, one might think of a reddish brown, an olive green, and a violet.
Too strict of an understanding of the color wheel may make you think that intensity ought to be lacking in the brown colors. After all, there is no brown on the outer ring of the typical color wheel, and so an artist may conclude that brown is merely the result of mixing two compliments. Actually, there are many very powerful and intense browns available to the pastel artist. I look to my Unisons for these, but others exist, too. The reason they can be intense should be obvious: they are derived from earth minerals, which become pigments. The purer the pigment, the greater the opportunity for color intensity. Having said that, keep in mind that many earth pigments are no longer made with the original materials, but are artificially or chemically produced, or mixed.
Other earth pigments include Venetian Red, Sinopia, Caput Mortuum, Olive Green and Green Earth, White and Black.
Via Handprint, here is a chart of watercolor earth pigments in a chart form.