10 : cadmium yellow (PY35), burnt sienna (PBr7), cadmium scarlet (PR108), alizarin crimson (? PR83), dioxazine violet (PV23), ultramarine blue (PB29), phthalocyanine blue RS (PB15:1), cerulean blue (PB35), sap green [hue], payne's gray [hue] Any painter who tries to do serious work with the "primary" triad palette quickly discovers it has four major deficiencies.
These are not problems unique to the "primary" triad palette. They are four dimensions of palette value that characterize all palettes in all painting or drawing media:
color mixing convenience, and
pigment material attributes
Chuck Long's palette choices illustrate the common tradeoffs that artists encounter on these four dimensions. Long paints in several genres (he is primarily a landscape and aviation painter), yet he resolves the palette tradeoffs with ten paints.
For comparison, here again is the "primary" triad palette scheme (below left), which in Long's palette consists of cadmium yellow (PY35), alizarin crimson and phthalocyanine blue GS (PB15), circled in the palette scheme (below left). What changes has Long made to this palette, and why?
the four dimensions of palette value
illustrated in the difference between the "primary" triad and Chuck Long palettes; numbers refer to the sections below
1. value range. As the gamut of media luminance (lightness) is the dominant information in an image, a large value range is almost always desirable. Reasonably dark black mixtures are possible with the "primary" triad palette, if you use a very dark blue or green blue paint; but they are tedious and inconvenient to mix and they do not produce the largest value range (depth of dark mixtures) possible in watercolor paints.
This is not an issue limited to painting: the simplest form of full color printing combines the CYM palette of three primary inks with the K of a carbon black ink. Photographers are taught to expose and develop images to exploit the full range of values the medium can provide. Oil and acrylic painters additionally require a white paint to reach the top notes of the value scale.
Long solves this problem by adding a cool, near neutral paint (the convenience mixture payne's gray) which is one of several dark neutral paints, sold under the marketing names indigo, neutral tint or sepia, that are made with carbon black (PBk6 or PBk7) tinted with phthalo blue, quinacridone violet or burnt umber. Payne's gray or indigo provide a strong black that is useful as a shadow color and, strongly diluted, can render cool, veiled skies or water. In effect, this addition combines the "primary" triad palette with the value design palette.
2. limited chroma. Adding a "black" paint essentially expands the gamut of the palette along the value dimension; Long makes three more additions intended to increase the maximum chroma across the orange, violet and green hues where the saturation costs of the "primary" palette are most severe.
The convenience mixture sap green (listed under PG7) enhances the chroma and darkness of green mixtures; pure green pigments such as phthalocyanine green or viridian are common alternatives. Dioxazine violet (PV23) brightens the notoriously dull violets of the "primary" triad (especially when these are mixed with alizarin crimson). This paint is also the mixing complement to most yellow greens, for example to produce the forest darks in the demonstration painting. Cadmium scarlet (PR108) enlivens the chroma of mixed reds, oranges and deep yellows. These additions yield almost all the chroma range that is possible with a palette of six paints.
3. color mixing convenience. If a larger gamut was his goal, why didn't Long use a pure pigment green paint, such as phthalo green YS (PG36) or viridian (PG18)? The most likely reason is that natural foliage greens look best in the gallery when painted duller than they appear in the field, so an intense, pure green pigment such as phthalocyanine green would create more mixing work yellow must be added to shift it toward a foliage yellow green color, then scarlet, crimson or purple must be added to dull the chroma; or, a deep yellow or orange paint must be available to mix the dull green directly with a pure green pigment.
A premixed sap green (or similar convenience greens such as hooker's green, permanent green or olive green) provides a generic dark, dull "home base green" that is quickly modified by the addition of any other paint on the palette. It does not need to be shifted very far or very precisely to get a convincing variety of green colors.
For similar reasons, Long adds burnt sienna (PBr7) as a warm "home base" for all manner of woods, earths, rocks, portrait complexions, dried leaves and grasses and as a reliable and gently neutralizing paint for the sap green. Again, the key is that the convenience paint creates an interesting and handy range of colors when tinted by any other paint on the palette; and a touch of the convenience paint can mute or shift the other paints in useful ways. For example, the granulating, dark mixtures of burnt sienna and ultramarine blue can be especially lyrical. And, speaking of mixing darks, the dark neutral paint saves long the trouble of mixing a dark neutral and is useful to mute and darken any other color: it can even make a muted green when mixed with yellow paint.
4. pigment material attributes. Most painters love pigments for themselves, as magically colored substances. But the typical primary triad palette consists of three synthetic organic pigments with very similar transparency, texture, staining and handling attributes. Most painters prefer greater variety in their paints.
Although pigment variety has become much less popular in contemporary watercolor brands, all include a selection of blue pigments that are the traditional reserve of pigment texture. Long's final paint additions, cerulean blue (PB35) and ultramarine blue (PB29), do not expand the chroma or value range of the gamut by very much. Their main attraction is their fleecy or grainy textures, which emerges in all the washes and color mixtures made with them. Long's delight in these texture possibilities appears in the poetic sky of the sample painting (above).
Other pigment attributes transparency, staining, tinting strength and lightfastness in particular are also important to many painters, and most professional palettes include some paints chosen for their specific pigment attributes separate from their inherent color or impact on the mixing gamut.
In that regard, the glaring defect in Long's palette is his choice of alizarin crimson (PR83), a fugitive pigment unsuitable for professional artistic work. It should be replaced with something anything! more permanent, such as quinacridone carmine (PR N/A), perylene maroon (PR179), quinacridone magenta (PR122 or PR202) or quinacridone rose (PV19), among many alternatives now available.
The sky, distant cliffs and receding depths of the lake all show Long's skill with mixing gradations of color to model aerial perspective or natural forms. The advantage of a limited palette eight paints, in this case is that these fine adjustments can be easily learned and reliably controlled. This lends the painting an expressive discipline that is only possible when materials are chosen to work well together, are intimately understood, and are utilized to their full potential.