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Category: sap green

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Monday Morning Art School: the color of earth

The earth pigments are our oldest colors, and they’ve served humanity well.

Dry Wash, oil on canvasboard, 12X16, $1159 unframed.

Years ago, I met an artist in Taos who told me that he never used the earths—siennas and umbers—in his paintings. I don’t remember his name, but I vividly remember his rationale. They were too close in color to the rocks of New Mexico. He did better to mix those warm shades.

That is very close to my own rationale for not having greens on my palette. The East is a predominantly-green environment. Using greens straight out of the tube is the best possible way to deaden your painting into a universal dull greenness without variety, sparkle or light.

Old Barnyard in New Mexico, oil on canvasboard, 12X16, $1159 unframed.

I’m teaching in New Mexico this week, so I have to adjust my own palette. My reliance on the earths has to ease up. However, my students are all from the south or east, meaning they’ll go back to a green landscape. I want them to take home the logic behind my palette, not an arbitrary rule.

The earth pigments are minerals that have been used in painting since prehistoric times. They’re primarily iron oxides and manganese oxides. We know them as the ochres, siennas and umbers. They’re extremely lightfast. In watercolor they granulate beautifully because of their large particle size. They’re relatively non-toxic* and they’re cheap. Those are all valuable properties to the painter, which is why they’re so widely used.

On the other hand, they look just like the earth because they’re made of dirt and rust (although we synthesize some of them today). They’re complex colors with lots of overtones. In mixtures they stubbornly retain traces of their own character. In a painting predominated by the natural reds and browns of the west, that can get pretty dull, pretty fast. If you want to know how a reliance on the earth pigments will turn out, see Rembrandt—great for Dutch interiors, not so good for American landscape.

Downdraft snow, oil on canvasboard, 12X16, $1159 unframed.

The world of greens cannot be simulated by something taken from nature. The pigments that give us green in nature—chlorophylls—are not lightfast. Instead, painters rely on an inorganic compound, chromium oxide green, which we know as viridian or chrome green. Chromium oxide is synthetic, but it does appear in nature as a rare mineral. It is relatively low-stain and inexpensive. It too granulates, which makes it valuable to watercolorists.

Chromium oxide green is a good workhorse pigment, far preferable to the deadening sap green that so many painters love. Sap green started as an unstable extract of buckthorn berries. What we buy today is a convenience mix based on phthalo green. That’s also true of the mixture marketed as ‘viridian hue.’ Paints based on phthalocyanine dyes are very high-stain and have a different color profile than the pigments they’re mimicking. That’s not to disparage the phthalo blue and greens; in themselves they’re lightfast, cheap, and have transformed the modern world.

Spring thaw along the upper reaches of the Pecos River, oil on canvasboard, 12X16, $1159 unframed.

Hooker’s Green is another convenience hue. It’s named after an English botanical illustrator, William Hooker, who first put Prussian blue and gamboge together to make a clear, light green. There’s nothing wrong with that mixture—but you should be able to make it yourself, not buy it out of a tube.

That’s true across your palette. You’ll have more flexibility and less expense if you stop buying convenience mixes and ‘hues’.

*Don’t ever fall for the idea that if it’s natural, it’s non-toxic. Mother Nature has hidden a lot of dangerous minerals in this beautiful earth, including cinnabar, galena, lead, asbestos and more.

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Monday Morning Art School: mixing greens

The rookie error for summer is to paint all foliage using the same basic color. You lose more points if it’s sap green.
Hazy mountain afternoon: Keuka Lake, by Carol L. Douglas. Available.
I have a student who reacts to my pulling out black paint by making the sounds of a rattlesnake at me. She’s been fully inculcated into the idea that black should be banned.
Michael Wilcox published a famous watercolor pigment guide called Blue and Yellow Don’t Make Green. Most of what it tells you can now be found on the internet, but it’s where I first got the idea to add back the banned black.
His point was that there are many routes to the same destination, and that to really mix colors, you need to understand what pigments you’re using, not work from trade names for colors. Consider sap green, for example—a staple of many plein air painters’ toolkit. It’s really a convenience mix made of a phthalo blue and some kind of yellow. The same is true of Hooker’s Green.
Chart courtesy of Victoria Brzustowicz
The single-pigment (‘true’) greens available are chromium oxide green, viridian, and cobalt green. Chromium oxide green is a lovely, heavy, natural green. Unfortunately, it outweighs everything it’s mixed with. Viridian and cobalt green are lovely, but expensive. Beware viridian hue—it’s just another phthalo in disguise.
By now, foliage has settled into a deeper, more uniform tone. The rookie error of August is to paint all your greens using the same basic color, modulating lighter or darker for highlights and shadows. You’ll have much more life in your trees if you know all the different ways you can get to leafy green. One of the most useful greens is black plus cadmium yellow lemon (or Hansa yellow).
Mixed greens, in oils.
The best way to navigate the colors of foliage is to avoid greens out of a tube altogether. A system of paired primaries gives you more options, avoiding the acidity of phthalo, the weight of chromium oxide green, or the soul-sucking darkness of sap green.
In my experience, bad paint mixing causes paintings to go wrong faster than anything else. Constantly over-daubing to modulate the paint color distorts the original drawing and makes a grey mush. If you’re confident of the color, you can apply it fast and accurately.
I make my greens on a matrix, which I’ve shown you both mixed (at top) and on a chart (below). I’m leaving for Castine Plein Air, but if I were teaching, I’d be drilling my students on green this week.
Swatches by Jennifer Johnson
First mix greens according to the chart, and then modulate your resulting greens with tints (meaning a mix of white and a color). The specific tints are unimportant, but the most useful one for landscape is a mix of white, ultramarine and quinacridone violet, making a pale lavender. It is great for atmospheric perspective.
Note that blue/black pigments are much stronger than the yellows. You need about half the amount of blue or black as you do yellow.
Your assignment is to hit paint swatches as closely as you can. 
The second exercise involves stopping at your local hardware store for a few paint swatches. These are Benjamin Moore brand, but you should be able to find similar ones elsewhere. There are two off-whites: one cool and one warm. There’s yellow, green, and two soft blues. Your assignment is to mix until you think you’ve hit the exact color. Then put a dot of it on the card to see how close you got. (If you’re working in watercolor, the dot goes on paper instead.)
Jennifer’s neutral swatches, up close.
I also have my students make neutrals using combinations of ultramarine blue with burnt sienna and raw sienna. I use ultramarine blue and burnt sienna as my standard dark-neutral, because it can go to the warm or cool side depending on how it is mixed. Raw sienna plus ultramarine is my go-to starting point for granite and the sands of our northern beaches.