Category: subtractive color

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Monday Morning Art School: the color of darkness

Painters spend lots of time thinking about the subtractive color system. We spend very little time thinking about the additive system. That’s a mistake, because this is the color of light.

A deer I painted years ago as a demonstration for my class. Shadows are the complement of the morning light.

Every artist is familiar with the three primary colors: red, blue and yellow, and their complements, the secondary colors green, orange and violet. This is the fundamental color wheel for the subtractive color system, or what’s used for paint and ink.

There’s another set that became more important in the 20thcentury, with the rise of electric lights and then electronics. These are the so-called additive color primaries, which are red, green and blue. This color system doesn’t have a color wheel, but it does have complements, which are shown below.

Additive complements (left) and subtractive complements (right). Courtesy Wikipedia.

Painters spend lots of time thinking about the subtractive color system. We spend very little time thinking about the additive system. That’s a mistake, because this is the color of light.

For painters, color theory is a balance between natural light (additive color) and their paints (subtractive color). That’s mind-blowing but they’re not alone in this challenge. Despite working in an additive-color medium, many web designers still think in terms of subtractive color. This system has influenced our aesthetics since the 18th century, and we don’t let go of what ‘looks right’ easily.

But in practical terms, shadows are the absence of light. If light is full-spectrum, then its shadows will be full-spectrum too. That means a white light will cast a grey shadow.

However, natural light is far more complex than that. It seldom shows up with all wavelengths being equal.

Sunrise, or the so-called ‘golden hour’ on Beech Hill. The shadows are definitely blue.

For this reason, artists have a useful rule: shadows are the complement of the color of the light. In the north on a snowy morning, golden light casts blue-violet shadows on the snow. In overcast light, the shadows are vaguer and full-spectrum, meaning they appear greyer. That’s easy to see, and demonstrates an idea that you can then generalize to all subjects. Although you should never trust your camera for color, I have included two photographs that show this.

Midday at the same location, the light is diffuse and so are the shadows.

It’s a mistake to get too attached to theory, however. For one thing, light is tricky. And for another thing, ‘primary color’ is another one of those constructs that we use because it’s useful, not because it’s absolute or provable. Our understanding and technologies are imperfect. CRT televisions of the 20th century were dull compared to modern LED screens. As technology got better, so did the color gamut, and what was considered ‘primary’ changed accordingly.

Most importantly, all these color systems are a dim mirror of the interaction of natural light and the human brain. Both are complex and imperfectly understood.

Light and shadows exist in the additive system, so your understanding of primaries is wrong if it’s based on what you learned in kindergarten. The complement of yellow in subtractive color is violet. The complement of yellow in additive color is blue. So, if the light is golden, the complement is more likely to be blue than violet.

At sunset, shadows appear black. There’s color in those darks, but our eyes can’t process it.

On the other hand, at sunset, the light is often red. The complement of red in additive color is cyan, but we almost never see any colors in the shadows at sunset. Instead, they’re just black, because we’ve hit the limit of what our poor rods and cones can process.

There’s a lot of latitude in what colors you can make your shadows, as long as you maintain the warm-cool balance. And—as always—all the theory in the world is no substitute for observation.

 

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Monday Morning Art School: why these specific paints?

All real-world limited palettes have gaps in them. Paired primaries work best.

The Athabasca River, by Carol L. Douglas
Savvy folk in the far north often reserve their peregrinations until March. That way, winter’s back is broken by the time they arrive back home. I knew that meant my current painting class would be scattering to the four winds soon. I had a neat little map of lessons laid out for them before they left town. Then my new grandson arrived early, and they didn’t get them in order. I’ll try to correct that here.
The three primary colors we learned in primary school are red, yellow and blue. Forget about any other color space you’ve learned about; they’re not relevant to painting.

Above are the three primary colors in subtractive color. This is the color space in which painters work, and it predates modern color theory. These three colors are the foundational building blocks on which all other colors are made.


Mention this to your nearest teenager, and he’s likely to pepper you with comments about other color systems. Ignore him. This is the color system in which pigments work.
Mix the primary colors in the first illustration with their neighbors and you end up with the secondary colors. A secondary color is always across the color wheel from a primary color.
Back in elementary school, we learned that if you mix a primary color with one adjacent to it, you get the secondary colors:
  • Green (blue and yellow)
  • Orange (yellow and red)
  • Purple (red and blue).

Importantly, a secondary color is always across the color wheel from a primary color. When you want to dull down (reduce the chroma) a color in a hurry, the fastest way to do it is to mix it with whatever’s sitting across the color wheel.
All blues are not created equal: the wavelengths of common painting blues, from Multispectral Imaging of Paintings in the Infrared to Detect and Map Blue Pigments, by John K. Delaney, Elizabeth Walmsley, Barbara H. Berrie, and Colin F. Fletcher, Scientific Examination of Art: Modern Techniques in Conservation and Analysis, the National Academies Press, 2005
All limited palettes are based on a simple red-blue-yellow color scheme. Unfortunately, in the real world, there are no pure paint pigments. They’re either warm or too cool, or they have overtones that muddy them up in certain mixes. This means that all real-world limited palettes have gaps in them, places you just can’t get to with the available pigments.
In practical terms, this can be useful to the beginning artist, as limited-palette paintings always feel integrated. That’s because they hit a limited range of notes. For the beginner, that avoids discordance, but it also means that he or she will never learn how to mix through the whole color universe.
The colors on my palette are a variation of primary colors. It’s the same principle, but there’s a warm and cool version of each of them.
This is why I use paired primaries on my palette. I have a warm and a cool blue, warm and cool red, and warm and cool yellow. This allows me to go almost anywhere on the color wheel without sacrificing chroma.
Why, then, do I have four more tones: yellow ochre, raw sienna and burnt sienna, and black? You don’t need these colors, actually; you can mix to get to any of these points. I use these iron-oxide pigments because they’re cheap and they make great modulators in places where white is inappropriate.
This allows you to go anywhere you want on the color wheel without sacrificing chroma (intensity).
All the colors on my color wheel are modern synthetic pigments (with the exception of the cadmium orange, which is a 19th century organic pigment). Conversely, the iron-oxide pigments are the most ancient pigments known to man. We know they’re not fugitive. Engraved ochre has been found that dates from around 75,000 years ago.