How to Understand Color Theory and Pigments

Red and blue don't always make purple. Sometimes they create a dirty gray instead. Starting with a basic color wheel drawn with pure tones, this article shows how to understand the pigments in the mediums you use and how to mix the colors you really want. Hot pink and blue often do make purple! It also covers blending, pointillism, crosshatching and impressionistic strokes to make optical mixing work when mixtures don't come out the way you want them to.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• A sketchbook or drawing paper
• Compass
• Ruler
• Protractor
• Colored Conte crayons, pastels, or oil pastels. If your set is smaller than 24 colors, add a large set of children's wax crayons.
• Black marker or felt tip
• Pencil
• Kneaded eraser
• Optional 12 color watercolor set
• Krylon workable matte fixative

1. 
   Twelve wedge color wheel with Primary Triad

   Mark up an empty color wheel in your sketchbook using the materials you already have. Start with a circle. If your protractor is a half round or round, you can use it to draw the circle in one or two passes and save yourself some work. Start at the top and mark two marks fifteen degrees away from center, so there is a wedge at the top and bottom instead of divisions. From one of those marks continue marking at 30 degree intervals all the way around the circle. Connect these dots with the ruler running across the center. This is your twelve-wedge color wheel diagram. Ink it with a waterproof ink marker or felt tip, especially if you use watercolor, paint or watercolor pencils for your color medium.
   
   Erase your penciling and any graphite smears when you're done so that they don't gray out your colors.
   
   Color in the top center wedge with bright sunny yellow. If you have a lemon yellow and a bright yellow use the sunny yellow. Lemon is one step more green than bright yellow. Count off three empty wedges, in the fourth empty wedge, fill with bright blue. Be sure your blue is neither greenish turquoise nor purplish blue-violet. Count off three more empty wedges and fill the fourth with bright red. Don't use orangy red or a purplish magenta, use the clearest true red you have. The red wedge should also have three empty wedges from the yellow one, if not, you miscounted and misplaced the blue.
   
   You have now made a color wheel with a Primary Triad on it. Whatever assorted color set of anything you have, those colors are probably in it. If you're using pastels or Conte crayons, blow the dust off and spray with Krylon workable fixative.

2. 
   Primary Triad and Secondary Triad together

   In theory, red and yellow mix in equal amounts to make orange. red and blue mix in equal amounts to make purple, and blue and yellow mix to form green. These should be exact bright colors called hues, but there is a reason we get pure secondary colors in almost every set of color mediums. It's because it rarely works out that way with real pigments. If you're using colored Conte crayons and scan the results with a Dell four-in-one scanner, you will get the same mixtures I do. But if you're using a different brand of pastels or some colored pencils or crayons or oil pastels, your mixes will be entirely different.
   
   Where possible, let's use pure hues from the set to finish the basic color wheel -- so we have something to match. I should mention now that my scanner plays hob with light green and yellow-green, it often washes it out to white. Hopefully it won't do that when we get to the next stage in the color wheel. This stage is the secondaries.
   
   Pick a bright middle orange, a bright kelly green, and a good clean purple. Fill in the middle blank wedge between yellow and blue with green, put purple between the blue and red, and orange between red and yellow. We'll try mixing after we know what we're aiming to get with the mixtures. I am using a large 48 color set of colored Conte crayons to get my colors for this, because the 12 color set I use for demonstrations has a nice green and no purple, though it has a beautiful blue-violet.
   
   The orange I used in my Secondary Triad (orange, green and purple) is in the little set too. But the greens in my little set were not the best mid-green for the diagram, one was a bit blue and the other definitely yellow-green. The purple wasn't in it at all. So if you do not have pure orange, green and purple, get some markers or some other medium that has these pure colors and fill the wedges. Use crayons if you have to, children's crayons come in all the primary, tertiary and secondary colors. I think they're all there even in 24 color sets marked by name.
   
   This color wheel is going to be used as a mixing guide when we try to create these secondary and tertiary colors by mixing. Blow off excess dust and spray with fixative again.
   
   Incidentally, the secondary triad -- orange, green and purple, or gold, green and purple, are the official colors of Mardi Gras. So if you like Carnival, keep them handy and let the good times roll!

3. 
   Full color wheel with all six Tertiary colors, pure hues

   This is starting to look good. You have the basic spectrum interspersed with white. Let's fill in the six Tertiary Colors -- each gets called by a combination name. Yellow-green between yellow and green, blue-green between green and blue, blue-violet between blue and purple, red-purple next between purple and red, red-orange, and finally yellow-orange working around the circle. Use pure hues.
   
   Hue means "what color it is," like red, blue-green and so on. Complements are colors directly across from each other on the color wheel -- and every one of these Tertiary Colors, which form two triads, has a good complement. Analogous colors are next to each other on the color wheel.
   
   If you pick out four analogous colors from the color wheel and take the complement of one of the middle two as an accent, you will have a color balance that has great harmony and plenty of pizazz in any drawing or painting you want to do with that. Like blue-green, blue, blue-violet and violet for example -- and then some bright orange fish swimming around in this reef scene. It will pop and grab notice.
   
   If you have a 24 or 32 color set of pastels, or a 24 color set of colored Conte crayons, you probably have all these pure hues and plenty of those colors not yet mentioned: browns and grays, olive greens, pink, peach, flesh, black, white... the color wheel colors need white at least if you're going to have a full range of color to draw squirrels, trees, rocks, things other than tropical fish.
   
   Tints are the colors you get mixing white and a color. Pink is theoretically a tint of red. But if you don't use the right red, you will get peach instead and not the bright sizzling hot pink of a petunia. For that you need a tint of red-purple, also called fuchsia or magenta.
   
   Shades are what you get darkening a color with black. But they do not retain the same color. Yellow and black make a nice olive green along the way, something I used to cheat and get an extra color into a color exercise using only tints of one primary hue. I got yellow, olive and black and it worked out great for a landscape. So it's not necessarily a bad thing that black can change the hue! If you want dark yellow, try using brown to deepen it.
   
   The color wheel was invented in the 18th century along with some research on optics and how light refracts. If you put light through a prism, you have a perfect spectrum.

4. 
   Color chart for 48 colored Conte crayons

   Now that you have a complete color wheel of pure hues, make a color chart of all the colors in your set. Whatever brand of pastels or oil pastels you use, if it isn't colored Conte crayons, it will not behave exactly like my examples. Many pigments are proprietary. The company that produces your pastels has colors other companies don't -- and pastels are a medium that doesn't mix very well in multiple layers. The more colors you have, the easier it is to draw what you want to. So after identifying the spectrum hues in your set (and any gaps you have in it), make a complete chart of every color you do have.
   
   Some are tints. But some of your pinks are different pigments used pure, not red pigment mixed with white filler. Some of the dark colors may be pure pigments too, not just a bright color mixed with black. Earth tone browns like Yellow Ochre, Burnt Sienna, Burnt Umber or Conte Sanguine are made from mineral oxides -- and they are specifically that color. So they mix in different ways than a rusty color you'd get by putting a little green into the bright red.
   
   If you are new to using pastels and chalklike mediums, I recommend the colored Conte crayons as they are relatively clean, very compact and tremendously versatile. They mix better than most pastels do and have many bright hues -- the full tertiary spectrum is included in the 24 color set, and the 48 color set has many neutrals and useful skin tones besides, as well as dark versions of primaries and secondaries.
   
   But if you're on a limited budget, choose a set of 32 or 40 half sticks or at least get a set of 24 assorted pastels. If your set is smaller, consider adding some individual sticks in the missing colors from open stock brands at your local art store.
   
   You can mix two colors in pastels by drawing lightly and blending with your finger or a tortillon. Going to more than two or three layers risks making mud, and creating ugly browns and grays that no longer carry any more color to brighten them up. You can lift off muddy passages (areas) with a kneaded eraser to get them back to where they'll take more pastel, but getting them clean again is very hard.
   
   So it's good to know what your colors are to begin with, and then to start creating mixtures on scrap paper before doing serious art. Or keep a spare sheet of paper the same color as what you're drawing on next to your pastels drawing. If you test every mixture before putting any pastel on your artwork, you can draw with confidence.

5. 
   Color wheel page with blended colors in complementary pairs and analogous groups

   There are two ways to mix color for a drawing. One is to literally mix the colors on the page, by blending. Combinations of two colors work well with Conte crayon or pastels and will produce a pure soft gradient one into the other depending on how much of each you use.
   
   Let's test the theory that mixing complementary colors will make some good neutral colors like those fine browns and grays in my color chart. Start with blue-violet and yellow-orange as the complements, or pick any pair you like as long as they are opposite each other on the color wheel. Notice that my pair is very different in value.
   
   Value is how light or dark a color is. Yellow has the shortest value range, at full saturation it's still not very dark. Blue-violet has the longest value range because it's very close to charcoal at its darkest. If you put a red cellophane filter over any color wheel to flatten it to just the values, you can tell how light or dark colors are.
   
   Draw a long shading bar for the blue-violet, smudge it till it's smooth and do the light end just by smudging. Do the same for the yellow-orange even if it doesn't change as much. Then draw the yellow one over a second blue-violet one, and mix them by smudging.
   
   Around the color wheel, I've done mixing bars for green and red, blue and orange, yellow and purple directly. Close to it and around it, I've mixed analogous colors in a smooth gradient, showing that mixing isn't pointless even if you can't quite match the exact color you're trying to create.
   
   A dark brown squiggle down at the lower left next to my blue-violet shading bar didn't match when I put red-violet with orange mixture next to it -- but I got Sanguine. When I repeated the mix and added a little black, I got it.
   
   Color mixing is trial and error. But there are some principles you can follow. This page now has lots of mixing bars in many different combinations and it does show that pink and blue from the 12 color set make a better purple than red and that blue do. I would probably get the best purple from the pink and blue-violet, because the blue-violet is a blue leaning toward red and the pink is a light shade of red that's leaning toward purple (closer to light magenta than salmon).
   
   So there's experimentation like this. But do we have to just guess as to which pigments mix well or not?

6. 
   Watercolor color chart and mixing chart.

   An old painter in New Orleans taught me this trick for mixing paints. It works better for painting than pastels, because in painting if you choose these colors, you won't even need other colors but white and a darkener, usually Payne's Gray, a bluish near-black, or black. A good 12 color watercolor set will have these colors and three earth tones -- Yellow Ochre (gold) Burnt Sienna (reddish brown like Sanguine) and Burnt Umber (dark cold brown, not reddish). It may not even have black because the dark brown mixes well with Ultramarine Blue to make black.
   
   So here's a color mixing chart and pure colors for my watercolor set. A cold yellow is lemon yellow -- lighter and more greenish. A warm yellow is the buttery bright yellow closer to orange. A warm red is the orangy red, a cold red is Alizarin Crimson which is almost purplish. The warm blue is Ultramarine Blue (closer to red) and the cold blue is Pthalo Blue Green Shade. For years I thought the purplish blue was the cold blue, being farthest from yellow, but it's not.
   
   Watercolors mix a lot more smoothly than pastels or Conte, so you can see the gradations of color that happen when you mix primaries to make secondaries. Brown, like Yellow Ochre and Burnt or Raw Umber, counts as a dark yellow for purposes of color mixing, while Burnt Sienna counts as a muted red. Sanguine is iron oxide and very close to Burnt Sienna color, a little redder.
   
   On the pastels mixing chart, notice how beautiful the analogous color blending was. When you add earth tones into your mixtures, you can start to get better muted tones and if you have colors like olive green that are pure pigments, you will get richer combinations than if you take a mixed color and mix it with another mixed color. The more different pigments are in a mixture, the more likely that two or more of them will interact badly and gray it out too much or leave it looking flat and muddy.
   
   Try to create mixtures that appeal to you, but blend at the edges of soft lines. With pastels and Conte crayons, it's much better to start close to the hue you want and only mute it a little bit.

7. 
   "Optical Fruit Salad" by Robert A. Sloan

   So, how can you mix colors without mixing? The answer is optical mixing with crosshatching, pointillism and impressionistic strokes. This is where pastels and Conte crayons really come into their own, because their colors are almost pure pigment, not much binder at all.
   
   In this small still life, the cherries and orange are shaded in pointillism. This is just like stippling in pen and ink. It's drawing by putting down dots closer together or farther apart. I started by drawing the orange entirely in orange dots and the cherries entirely in red ones, with some dark areas where they were close together and light areas and some significant white highlights. Then I used yellow to shade more on the orange, and pink on the cherries. I used other colors in the shadows, blue and blue-violet. I put some orange in the cherries and some red in the orange. Play with color when you're doing pointillism. Dots of complementary colors next to each other sizzle with excitement -- and when you move farther away, or look at it in the thumbnail, they blend to form smooth gradual changes in hue and value.
   
   George Seurat was a famous painter who invented pointillism and did enormous oil paintings entirely by doing little eighth-inch size dots in bright primary and secondary colors. I remember he used a lot of pink and blue in the bright green grass in the Seurat painting I saw. Pointillism is a powerful style that takes patience and a good sketch to do well. The larger the area, the smoother the changes.
   
   Impressionistic strokes follow the shape of the object and also juxtapose colors to visually blend them. My mango is done with impressionist strokes that overlap, don't blend, and use the same principle as pointillism for visual mixing. Van Gogh's oil paintings and Monet's pastels are good examples of Impressionism. Try doing Impressionist drawings outdoors in bright sunlight and work fast. Use bright colors and mix optically to get the impression of what you see, especially the colors it turns in odd light like sunset or a blue evening. The deepest shadows under the edge of all three fruits are black impressionistic strokes.
   
   Crosshatching is another way to optically mix colors. I layered bright blue, blue-violet and brown to make bluish shadow.
   
   Look at this still life in thumbnail and enlarge it to see how visual mixing works to blend without blending. Try copying it, or try these techniques on another sketch like the Easy Rose.

Tips & Warnings

• Work large when doing pointillist pastel paintings. The more area you have to work with, the wilder your shading combinations can get. Have patience!
• Work fast with Impressionist techniques and try to capture the colors you see, not the colors things are supposed to be. Use complements to create neutrals, but put browns, pinks and grays in where they're not expected.
• Blend on a saucer by scraping powder from your pastels and mixing with a cotton swab before applying a dry wash.
• Don't get pastel pigment into your mouth or eyes, especially if your pastels are artist grade. Many mineral pigments are toxic and so are some vegetable dyes.
• Don't breathe pastel dust. If you do a lot of pastel drawing, wear a face mask the way house painters do.
• Make sure you have plenty of ventilation both for pastel dust and for fixative fumes.

Resources

• Author's DeviantART page for more samples
• Dick Blick for supplies and information on pastels and Conte crayons
• Unrestricted Stock downloads from DeviantART unrestricted stock group for photo references
• DeviantART to show off your work