1 : ivory black (PBk9), lamp black (PBk6), graphite gray (PBk10) or india ink; or sepia, neutral tint, indigo or payne's gray; or sepia combined with one or more "earth" pigments and a white paint This is the most basic of all palettes: a single dark, near neutral pigment diluted across all value levels from near black to paper white.
A monochrome palette, typically called a value design palette by artists, is limited only to the achromatic series black, grays and white produced by vine, ivory or lamp black. (India ink can be used in a very similar way to a black watercolor.) The illustration painting, an early work by Paul Klee, is typical of his watercolors in the period 1908-11, when he painted almost exclusively using only a black paint (occasionally adding white gouache for highlights).
By eliminating color, and using a dark paint with little or no pigment texture, the artist must focus on two key design elements: value structure and brushwork (brushed texture). The palette puts the focus on the value composition of a painting, and emphasizes problems of light and atmosphere. And without color to distinguish among objects, brush technique becomes much more important. Precise edges, perfectly graded shadows, diverse brush marks (including drybrush), and the texturing effects of blooms, blotting, washes and resists are all displayed more dramatically.
The monochrome palette is a wonderful discipline when used with a book of black & white photographs among my favorites are Ansel Adams's landscapes, Robert Mappelthorpe's flowers, Edward Weston's nudes, Irving Penn's platinum prints, Man Ray's portraits and still lifes, and Paul Strand's abstractions. Copying (or reinterpreting) these images sets you grappling with value composition directly. The palette also provides plenty of exercise in the brush skills necessary to model subtle changes in light across rounded surfaces or diffuse shadow edges, or to show the effects of air and humidity through value alone. Cloudy skyscapes are probably the ultimate technical achievement with this palette.
Because of their low specific gravity, tiny particle size and extra helping of dispersant, carbon pigments are among the most difficult to control in watercolor paints. Active wet in wet, they diffuse and backrun readily, and tend to leave tiny, bright pinholes in wash areas that were solid color when wet. They also lighten significantly as they dry, but in proportion to their value when wet: tints shift very little while the darkest color shifts a lot. The painter must anticipate drying shifts by applying dark values darker than they should appear in the finished painting, while avoiding the raw paint buildup that produces bronzing or glossy, scabby looking color.
There is a surprising amount of color variation in paints that might all be considered to be "black". Justin Johnson writes: "I've gone from neutral grey (too purple) to lamp black (not bad) to mars black (too granulating in washes when your approach concentrates on gradually building up darker tones) to ivory black (warmer and more pleasant than lamp) to graphite grey. The last was the immediate winner warmer yet more neutral than ivory, with the latter's slightly yellow cast. The iridescence is almost unnoticeable at any grey darker than 75%, but it seems to very subtly add depth and richness. Next to it, ivory black washes look flat and aged like newspaper."
Finally, carbon pigments discourage fussing. They are very nearly impossible to rewet and lift, frustrating any attempt to lighten areas that are too dark or to edit messy edges or accidental drips. A second or third layer of diluted color can be used to darken areas that dry too light, but this is a crutch that gets tedious very quickly. Klee habitually used partly overlapping layers of paint to create geometrically patterned value and color gradations in his watercolors, but each of his layers is exactly judged a skill he learned by using a monochrome palette.
There are two chromatic variations to the value design or monochrome palette:
1. Tinted Dark Shade. The first is to use a dark shade convenience mixture that consists of carbon black tinted with a specific hue. Paints of this type include sepia (tinted red or orange), neutral tint (tinted violet), indigo (tinted blue) and payne's gray (tinted green). Any of these paints gives a nearly complete value range, but they are intriguing because they will produce a changing series of very muted hues as they are diluted, creating a beautiful duotone effect. And these effects vary considerably across paint brands. The indigo paint made by Daniel Smith dilutes into perfect metallic gray tints, while the same "color" made by MaimeriBlu dilutes into a delightful pale green gray.
2. Series In a Single Hue. The second variation is to combine the black pigment with a chromatic paint, to produce a very broad contrast in the chroma of color mixtures within a very narrow hue range. This is the harmony of scale that the 19th century color theorist Michel-Eugène Chevreul included among his six color harmonies.
The most popular strategy is to combine either a lamp or ivory black, or the convenience dark shade sepia, with one or more red or orange "earth" pigments, such as burnt umber (PBr7), burnt sienna (PBr7 or PR101) or venetian red (PR101), or any iron oxide paint labeled transparent brown, red, or orange. If these paints are used on tinted or colored papers, then a white paint such as titanium white (PW6) can be added as well (palette diagram, left). This selection of paints mimics the basic color world of sanguine chalk drawings (popular since the Renaissance) and the color variation found in Conté crayons. This palette is very effective in portrait work, and dramatic when used with a harmonizing or contrasting tint of paper. (In lieu of tinted paper, a white paper can be prepared with a wash of very diluted paint.) The hue range can be expanded by adding a yellow orange iron oxide (gold ochre, PY42), but in general a distinct yellow hue detracts from the effect.
I have also tried value paintings with a synthetic black that is mixed from red, green and blue violet pigments. Slightly changing the proportion of each pigment in the mixture allows the painter to shift the hue bias, but as three paints are involved and none of them are "primary" colors, this method can also be considered a variation on the painting strategy that underlies the Velázquez palette.
It's surprisingly difficult to reproduce a black and white photograph with a single pigment. Much of the effect of a photo arises from slight differences in the mid values, and many painters lazily lean on hue contrast to increase the apparent differences among the midvalue areas of a painting. Without hues to distract you or help you, accurate values must be painted directly. If a black and white original isn't challenge enough, try painting from a color photo.
Even without hue, the warm/cool contrast can be expressed by using lighter values to represent warm surfaces and darker values to express cool; the ancient color theory was substantially based on a value ranking from white to black. Modern color science would define the value ranking as white, yellow, orange, green = red, blue, purple and black.
See the section on the apparent value of colors and the artist's value wheel for suggestions on how to see accurately the value or lightness of different hues.