This month, we flee the endless winter and return to the warmth of the studio, with a decidedly warmer subject than snow: the yellow onion.
Figure 1: Munsell colors for February 2013
A still-life staple, the onion offers a surprising amount of variety within a single hue. 7.5YR covers just about everything you see here. A green stem will push into GY (and we’ll see plenty of that in this spring’s articles), but the body of the onion, its skin and its base are mostly within the 7.5YR gamut.
The main body strikes a local color of about 7.5YR 5/6. This rich, mid-level reddish-brown is higher in chroma than the grasses and leaves we’ve looked at recently. Notice also that this is firmly a base color. As it turns into shadow and light, it loses chroma as it tends towards dark and white. The specular highlight of the onion’s skin approaches the pure white of the light source, N 10/ for all intents and purposes. The 7.5YR 5/6 color here matches the area at the top right of the chip.
The darker flakes of skin can be seen to be holding the same value, but less chroma at 7.5YR 5/4. Single layers of skin are more translucent and generally lower in chroma.
The lightest areas of skin, where the stem has dried, come in at 7.5YR 8/2. It is sometimes tempting to think of such areas as white, but this example, even at its lightest, is two full value steps below white. A careful comparison of this area with the specular highlight on the surface makes this clear. The entire value range of local colors in this sample is four steps, from 5 to 8, which is unusually high for a single organic object, but this wonderful variety is one reason the onion is such a popular (and challenging) subject in paintings.
Finally, dark spots and blemishes can push this range even farther. The small freckle-like spot in our example drops down a full value step below the local at 5YR 4/4. This will be slightly more chromatic than the value 4 range in the shadow as the form turns. It also shifts in hue slightly towards red as it drops in value.
With these four basic colors, you can cover most of the range of the yellow onion. Light and dark tending toward white and black, simple strings can be plotted in advance that will provide the full range. Slight hue variations towards red and yellow (holding chroma and value steady) can provide pleasing “vibrations” for more sophisticated renderings, but simple renderings can be done beautifully with this month’s simple palette.