Outside of color theory, in the real world where color really matters, is color practice: mixing your own colors from paints.
why make a paint wheel?
Paint wheels are a very effective way to learn the complex landscape of the color space, the best methods for mixing paints, and the handling attributes and mixing behavior of your palette pigment selections and brand(s) of paints.
Many watercolor instructors recommend that you disply your palette color mixtures as a mixing plaid a grid of color with vertical stripes glazed over horizontal bands. This is adequate to show the relative intensity and opacity of each color in comparison to all the others, but the individual mixtures get lost in the color clutter, and the color mixing is limited to glazing (one color painted on top of the other).
schematic of a finished paint wheel
With the paint wheel, color mixtures are displayed as locations within the visual color wheel, and the appearance of the mixtures reveals the logic of subtractive mixture saturation costs the chroma of a mixture decreases as two mixed colorants are farther apart around the hue circle. Within this basic framework, even subtle differences among painter's palettes are easy to see.
Because the paint wheel requires many different color combinations painted into different locations within an intricate pattern, you quickly develop an efficient method for working with paints and skill in using your brush to get paint onto paper.
You also learn the characteristics of different mixing techniques. Unique color effects result from mixing paints wet on the paper, or by glazing, or by premixing on the palette and making paint wheels using each method helps you see these differences clearly.
With a paint wheel, all the basic skills following a pattern, preparing and mixing paints, keeping colors pure, applying paint with the brush, rinsing the brush between different colors, mixing paints (sequencing glazes, mixing wet in wet or charging wet paint), working around wet paint areas are practiced at the same time, and everything is made more factual because there is no distracting picture you are trying to reproduce.
A paint wheel is also beautiful. The mandala shape, visual texture and radiant fullness of color, and the repeated movements of mixing and brushing the paint, make the paint wheel a soothing and insightful meditation on color and the physical act of painting.
how to paint a hue circle
But before I launch into paint wheels ... some painters may be content simply to paint out a categorical hue circle, showing the variety of hues, in approximately their correct location as a perceptual hue circle, using the most saturated single pigment paints and their mixtures. This is an effective help in learning to discriminate between similar hues (orange yellow and yellow orange, for example), and a handy reference for evaluating the effects of different light sources on color appearance.
A template for the hue exemplars as a hue circle is shown in the diagram (below). Simply draw a circle to fit your choice of paper; use a protractor to divide the circle into eighteen 20° segments; and use a circle template to make 18 hue exemplar areas centered on each "spoke", with an extra exemplar area for black or gray in the center.
template for a simple hue circle
Any selection of paints can be used. I chose the most appropriate pigment(s) using the CIECAM hue plane, and then determined the relative proportions in specific hue mixtures from the relative pigment locations around the hue circle.
The table below shows an efficient recipe for all 18 hue exemplars, using only 7 common and easily obtained pigments (referenced by CI name). The hue of the pigments chosen for these mixtures should be very consistent across brands, but use this cadmium paint guide to identify the exact hue of the different cadmium paints offered by different paint brands.
The proportions shown are visual proportions; that is, if the ratio is 1:2 you use whatever mixture of paints necessary to get a completely dry visual color that is about 2/3d's of the way between the two paints. If the hue comparison seems difficult, aim to get the color lightness in the right proportion. The larger hue steps are a little harder to get right: paint out the mixture and let it dry first, before you commit it to your work. For the violet red to violet blue span, mix the violet first, then paint in the two intermediate steps. Black is mixed by combining all the paints.
a simple hue circle
The example (above) does not use the same pigment recipes as the table: maganese violet and cobalt violet were used to mix some of the violet steps. I don't recommend this, as it adds a distracting variety of granulation texture to the exemplars.
Of course you can create a similar hue circle, using only pure pigment paints, or a smaller number of paints the three "primary" colors (benzimida yellow, quinacridone magenta, and cobalt teal or phthalo blue GS) are a good alternative. For that project, just identify the pigment nearest to each 20° spoke in the CIECAM hue plane. However, this also introduces a larger variation in both the lightness and chroma of the hue exemplars, something that you avoid by basing them on mixtures from a smaller number of paints.
how to make a paint wheel
Here I explain in detail how to lay out and paint a paint wheel. The key points:
The 12 swatches are equally spaced around the circumference of a large circle, aligned as 24 "spokes" of equal hue.
Color mixtures spiral toward the center of the wheel as the two mixed paints are farther apart, so that the mixed color is always roughly on the mixing line between the two paints used to make it.
Neutrals mixed from complementary paint colors are arranged around the inner circle, showing the variety of grays the palette can produce.
Mixtures that match the hue of the paint at the outermost end of the spoke will display differences in the lightness and chroma of the same hue mixed by different paints.
Mixtures on the same spoke that were made with equal proportions of the two mixed paints do not match the hue of the paint at the end of the spoke when there are differences in the tinting strength of the two paints; the hue is shifted toward the paint with the higher tinting strength.
The mixture swatches are large enough to give a reliable impression of the mixed color.
The paint wheel is a beautiful mandala like pattern when completed, and shows many peculiarities of the subtractive mixing landscape as a single image.
Basic Layout. I build paint wheels around the twelve point color wheel. This uses 12 different paints and requires 66 unique paint mixtures usually more than enough to explore the range of pigment effects around all parts of the hue circle.
The paint wheel measurements I've found most convenient are shown in the diagram and listed in the table (below). The key measurements are indicated over the mixture pattern for two opposing colors of paint (yellow and blue violet).
paint wheel measurements and single color swatch patterns
To make each measurement system easier to work with, the metric measurements make a slightly larger wheel
These measurements are tailored to fit on a Fabriano Artistico 14" x 20" watercolor block, which is widely available in the USA and Europe; the dimensions also work well on a watercolor half sheet (15" x 22"). You can add ¼" (0.5 cm) to all the radius measurements (swatch lengths) if you want the wheel a little larger (easier to paint into) ... or you can multiply all the measurements by any factor to scale the wheel larger or smaller, as your paper size may require (multiplying by 1.5 increases the wheel size by 50% or 6½ inches). I recommend you don't go smaller than 12 inches in diameter. The swatches are too small to display the colors distinctly, and greater skill is required to lay on the paint.
Constructing the Wheel. Before starting, the paint wheel outline should be laid out lightly with a hard graphite pencil, compass and a CThru ruler, in the following steps:
(1) Lightly draw the central segment of the two diagonals from the opposite corners of the sheet: the point where these cross is the center of the sheet.
(2) Measure the radius of the paint wheel from the center using your ruler, and use a compass to scribe (1) the circumference and (2) the inner circle. (If you want to prevent an unsightly hole in the center of the paint wheel caused by twisting the compass around its pin, first secure a square of cardboard or heavy paper over the center of the paper with masking tape.)
paint wheel layout (steps 1 & 2)
(3) Draw a vertical line through the circle center (the compass pin hole), perpendicular to the top edge of the paper. (Measure the distance of the pin hole from the paper side edge; mark this distance along the top edge, and rule a lightly drawn line between the two points.)
(4) Align a protractor to this vertical line and centered on the pin hole, and divide one of the half circles (180°) into 12 equal units (15° apart). Then flip the protractor over, and mark in the same way on the opposite side. (If possible, use a 360° or circular protractor instead.)
paint wheel layout (steps 3 & 4)
(5) If you intend to use a 1/2" acrylic flat brush to apply paint, then you can rely on the width of the tuft to paint the swatches by painting on both sides of the central spoke (see example paint wheel below). All you require are the central spokes for each hue angle.
Use an 18" C-Thru ruler (image, right) or similar tool to draw the paint wheel spokes through the matching protractor marks on opposite sides of the wheel; continue the line to the outer circle on both sides. (Do not draw the lines inside the inner circle; there is nothing to paint there, and the lines are unsightly.) The circle is now divided into 24 equal slices.
(6) Using the compass again, scribe the six inner circles of the paint wheel. It greatly reduces confusion when painting the wheel if you break the circles into short arcs that only cross the spokes that each circle is used to divide (these are the alternating long and short spokes, indicated by "L" and "S" in the measurement table, above.)
paint wheel layout (steps 5 & 6)
Your layout is done; it should take you about 15 minutes. Skip to step 8.
(7) If you intend to use a round brush, or you want an extraordinarily finished visual result, you will need to draw the swatch edges as two parallel lines, either 12cm or 1" inch apart, without drawing the central spokes.
Carefully mark the hue angles with the protractor as before, and scribe the inner circles as before. If you have taped a card at the center of the wheel (to protect the paper from the compass pin), remove it.
Now use a "C-Thru" brand plastic ruler, the 18" long one, to scribe the lines. Simply align the ruler over the protractor marks so that the marks are spaced 4 grid squares (=½") from the ruler edge, and scribe the line. Repeat 24 times around the wheel to complete one side of each long and short spoke. Then rotate the paper a half turn to reverse direction, and continue to finish the opposite sides.
To minimize visual clutter, don't rule inside the 2¾" (6.5cm) circle.
Next, for the single stroke swatches near the center, repeat the same operation, but this time align the protractor marks so that they are just 2 grid squares (=¼") from the ruler edge. Make sure you keep track of which are the long swatches (on the short spokes) and which are the short swatches (on the long spokes). They alternate, long short, all the way around the wheel. Again, rotate the sheet and continue to finish.
alternate paint wheel layout (step 7)
If you can't find a C-Thru ruler, then you must use a long ruler or yard/meter ruler, and extend the protractor marks to the circumference of the wheel, mark the measurements on both sides of the lines for both the 1" and ½" swatches, and then scribe the lines. (The marks for a single long and short spoke are shown as green and red dots in the diagram, above.) This takes quite a bit longer to do!
Your layout is done; it should take you about 30 to 45 minutes.
(8) Remove the paper used to mask the compass pinhole.
(9) Use a kneadable eraser to gently remove stray marks if desired.
Brushes and Painting Strategy. The 12 numbered swatches around the outside of the wheel are the samples of the 12 unmixed paints.
For the glazing or wet in wet paint wheels, I make these swatches with two strokes of a 1/2" acrylic flat brush, side by side to form a large rectangle, 1" wide by 1¼" long, starting at the arcs with radius of 6½", 5¼" and 4" (long spoke) or at radius 6½" and 5¼" (short spoke).
The last (inner) swatch is a single stroke, starting at the 2¾" (long spoke) or 3½" (short spoke) radius.
Again, you should use only a 1/2" acrylic flat brush for painting, as a sable flat tuft will spread out too wide under the brushstroke pressure to match the swatch dimensions. You can of course use any brush you want but it's much harder to do the work, and the results are usually so ragged that they distract from the color comparisons.
If you use a round brush and mix paints on the palette, which produces the most finished results, then a #6 brush is usually the most convenient.
Selecting Your Paints. Now choose the 12 paints you want to use in the paint wheel.
a C-Thru 1/8" grid plastic ruler
you will need the 18" long version
The diagram (below) shows my preferred allocation of hues, both as they are spaced in a perceptual hue circle (inner circle, where the distance between hues is equal to the perceived visual difference between them) and as they will be spaced in the paint wheel (outer circle).
perceptual hues and paint locations in the paint wheel
I discuss different paint selections in the next section, but the strategy shown above expands the space allocated to red hues and contracts the space allocated to violet hues. This reflects the prejudice that warm and blue hues are more important for an artist to understand than violet hues, and the fact that there are very few viable violet pigments available in artists' materials.
Preparing Your Paints. Mix the 12 pure colors with water before you start painting. Squeeze out roughly 1" of tube paint into separate wells or mixing cups of your palette, and dilute them with an equal quantity of water 1/2 tablespoon to 2 teaspoons gives plenty of paint at an optimal saturation. This ensures that you start with the same concentration of paint for every color, and the colors are at their peak chroma.
When diluted in this way and mixed in equal proportions, mixtures of two paints will display, as shifts toward one color or the other in the hue of the mixture, any differences in the pigment tinting strength and paint pigment load (concentration of pigment) in the brand(s) of paints you're using.
If you want to match the hue of each spoke of the paint wheel, you must adjust the mixtures by eye. The alternative is to adjust the dilution of your paints so that they all have equal tinting strength by adding more water or more paint to each mixture.
The compromise is to add more paint to the pigments with low tinting strength (ultramarine, virdian, cobalt and iron oxide pigments), and less paint (or more water) to the pigments with high tinting strength (cadmiums, phthalocyanines, pyrroles, dioxazine violet). Even if the tinting strength is only roughly the same, it will be much easier to match the mixtures to the spoke hues.
Mixing Strategies. You can mix paints in at least three ways: (1) by glazing, (2) by mixing on the palette, or (3) by mixing on the paper. Each method raises slightly different problems and teaches you different things about the paints.
circle pattern of paint mixtures (for yellow)
1. The fastest way is to mix by glazing (painting one pure color on top of the other). First lay down pure swatch of the "primary" yellow color (the pure color on the circumference of the wheel) at long spoke 1, then paint the same yellow into the 12 rectangular areas to be mixed with yellow inside the wheel, 6 on either side of the pure hue swatch (see the pattern diagram above). Proceed from the outer to the inner swatches, and save for last the two small, single stroke swatches on the inner circle.
Rinse your brush, and proceed in the same way with the paint directly opposite the color you have just painted this is long spoke 7 (blue violet) for yellow. Paint the 13 swatches as before, and save the small overlapping swatches at the inner circle of the wheel until last.
By now the yellow paint should have dried completely, so that paint can be glazed over it; if not, wait until the paint has dried.
Move to the next color toward red (deep yellow, long spoke 2), and repeat the same pattern. You will paint the pure patch, and 11 new swatches. At one swatch (the short spoke between yellow and deep yellow) you will glaze the deep yellow over the primary yellow patch you just painted; at another (the short spoke between red and violet red) you'll glaze the yellow over the blue violet. Let the colors dry, and move to the color opposite deep yellow (blue, at long spoke 8), which will be glazed over yellow, deep yellow and blue violet. Paint the two inner swatches last, to give the deep yellow sufficient time to dry. And so on for all the rest of the colors ... you'll paint the pure patch, and 11 foundation or glazing swatches, depending on the number of colors already painted.
By applying the twelve paints in a specific sequence, rather than in strict counterclockwise order, you can change which colors are glazed on top of any others. The usual method is to glaze the darker valued paint over the lighter valued paint, and the more transparent paint over the more opaque paint, so you may want to lay down the swatches for each paint in order of increasing dark value and/or increasing transparency for example, (1) yellow (Y), (2) orange yellow (OY), (3) green blue (GB), (4) yellow green (YG), (5) red orange (RO), (6) green (G), (7) violet red (VR), (8) red (R), (9) blue (B), (10) blue green (BG), (11) blue violet (BV) and (12) violet (V). (Refer to the color locations in the diagram above.)
sequence of swatch painting in double glazing
A: one side of the swatch is painted with the first paint; C: the entire swatch is painted with the second paint; C: the other side is painted with the first paint
However, because the outer swatches are painted with two brush strokes, you can easily display the two paints glazed in opposing order, with the two samples side by side for comparison (diagram, above).
The procedure is scripted. For each new color you paint in, first paint the double strokes in the swatch on the circumference. Then for each remaining double swatch, if there is no paint in the swatch, then paint a single stroke into one half of the swatch area (A, above); leave the two single stroke swatches unpainted on one side (it doesn't matter which, but be consistent). As you work, if you encounter a swatch (double stroke or single stroke) that already has a stroke painted into it, then paint over the entire swatch (B, above). Once you have completely painted the paint wheel in this manner, go back and paint over any unglazed color with a final stroke (C, above). (You can see the result of this procedure, especially in the violet mixtures, in the split swatches of this mixing wheel.)
Always wait until a paint has dried completely before attempting to glaze over it, and paint the glaze as a single brush stroke so that you don't dissolve and lift the paint underneath.
With this method it does not matter which order the paints are applied, so you can choose the next paint to apply in a way that minimizes the time you have to wait for paint to dry.
The glazing method helps you to learn the transparency, tinting strength and particle texture of paints, and glazing brushwork. There is no paint mixing required.
A glazing paint wheel can normally be finished within 1 to 2 hours.
2. To mix on the palette, prepare all the paints in advance, as before.
First, go around the paint wheel and paint in each pure paint sample around the circumference. This lets you confirm visually the color selection before you put any more work into it, and it provides visual examples of the spoke hues, which you will need in order to match the hue of the mixtures.
Between each color, thoroughly rinse your brush and shake out excess water, to keep the paint colors unpolluted and at a constant dilution.
Now overcharge your brush with paint, hold it over the paint well until it stops dripping, then wick the brushful of paint into a clean paint well or palette area; do this in a series with the first six paints. Now go back, and wick into the first paint sample the same amount of the corresponding mixing complementary paint: for example, blue violet with yellow, blue with deep yellow, teal with red orange, blue green with red, green with violet red, and yellow green with violet. Mix this up with the brush, and paint the mixture into the two opposing short swatches on the inner circle. Rinse, and repeat for the other five complementary color mixtures.
Note that you paint these complementary mixture swatches into the smaller (1") inner strokes, and you paint them at right angles to spoke of the two colors you are mixing (see the diagram above).
The reason that you paint these complementary mixtures first is so that you can assess the relative tinting strength of the two paints, and make dilution adjustments (adding more paint or water) as necessary to make the rest of the paint mixes easier to do.
That work done, rinse your brush and wick out ten brushfuls of the yellow paint into clean mixing wells or palette areas. Rinse the brush, pick up a brushful of the first mixing color, mix it with one of the yellow color samples, and paint this mixture in the appropriate position. Rinse the brush, and pick up, mix and paint the next mixing color. Continue until all the yellow mixture swatches have been filled in.
It's advisable to test the mixture of paper first, to make sure the hue matches the spoke it is painted on. If you must adjust the mixture, thoroughly wick out the mixture you have from the brush, rinse it, and pick up the desired paint.
After you have finished with this first color, clean the palette and lay out nine brushfuls of the next base color: one less, because you have already done its mixture with yellow. Mix and apply all remaining colors, and repeat. Each time you wick out a new base color, you reduce the number of samples by one. For the last color, you will only wick out a single paint sample.
This method helps you to learn the relative tinting strength of paints, palette mixing skills, paint brush accuracy, and working over and around wet paint areas. You can apply the paints in any order.
A mixing paint wheel takes considerably longer, up to 4 hours, depending on the amount of care you invest into painting the swatch corners and matching the paint mixtures.
3. The third method is to mix on paper, by first laying down one color, then charging the swatch with the second paint while the first paint is still wet. This is the hardest mixing technique to do in a controlled way. The simplest method is to lay down one of the paint colors as one stroke of the double stroke swatch, or one half the length of the single stroke swatch, quickly rinse the brush thoroughly, squeeze the tuft dry with a paper towel, charge the brush with the second paint, and apply it as the second stroke of the large swatch or the opposite end of the single stroke swatch. When you apply this second color you must paint into the first stroke so that the two paints puddle and blend. You must rinse the brush and apply the second paint quickly or the first paint will dry on the paper; you should also use juicy applications so that the swatches have ample liquid to diffuse.
This method is most attractive if you absolutely do not attempt to blend or adjust the paints with the brush after they have been applied let water diffusion and evaporation mix the paints. This means you cannot tilt or jostle the paper as you work. You have to move quickly, think quickly, and know what you're doing. It's fun if you know how!
With this third method, the paint staining, diffusion behavior wet in wet, and paint application skills become more of a focus.
With this method the swatches take much longer to dry; depending on your weather and paint viscosity, it may take a day or more to complete a paint wheel, but most of that time is spent waiting for the paint to dry that is, doing other things.
lessons from a paint wheel
Trial and error with paint wheels changing the hues in the twelve positions around the wheel, the paints for each hue, the manufacturers for each paint taught me the many tradeoffs I faced in choosing a working palette.
A paint wheel based on the tertiary color wheel forces you to choose twelve paints to fill each color slot. This may seem to be an arbitrary and silly exercise. But it leads you to consider the alternative paints available for each color slot, and to think about the effect that one paint selection has on the mixtures it makes with all other paints. These are the two fundamental problems you must face in any palette design.
The wheel below is based on a palette I discovered with the paint wheel method after about thirty variations in the selection of 12 paints. It's not the selection I would use now, but it illustrates some of the tradeoffs you must consider when choosing paints.
The paints used are (reading counterclockwise around the twelve color points of the tertiary color wheel): (1) Winsor & Newton aureolin (or Daniel Smith hansa yellow light), (2) Winsor & Newton indian yellow (or Daniel Smith hansa yellow deep), (3) Daniel Smith perinone orange, (4) Daniel Smith perylene scarlet (dark and slightly subdued), (5) Winsor & Newton quinacridone red, (6) Winsor & Newton quinacridone magenta PR122, (7) Winsor & Newton winsor violet (dioxazine), (8) Winsor & Newton french ultramarine blue, (9) Winsor & Newton prussian blue (now I would use Winsor & Newton phthalo blue GS), (10) Winsor & Newton cobalt turquoise light (more evocative than cobalt turquoise), (11) Winsor & Newton winsor green BS (winsor green YS is not as dark or powerful), (12) Winsor & Newton permanent sap green. (For my current selection, see the end of this page.)
I tried paint wheels with the siennas and ochres included in the orange to yellow slots, but found it was better to explore these pigments as part of a separate earth palette.
Paint wheels will let you explore every part of the color wheel, the saturated colors with the unsaturated, the mixtures you are familiar with (blue and yellow) with the mixtures you may never tried (teal and violet).
There are many intriguing corners of the color wheel the dull color areas under yellow, orange and green blue, for example and a whole world of paint textures and wet in wet color effects. Take your time, and enjoy the process.
The paint wheel reveals that each single paint produces a whole circle of color mixtures, like a bouquet. You learn to understand paints in these terms, and choose a paint for the whole bouquet, and not for the color of its "pure" unmixed blossom.
Paint wheels taught me that I had been plucking the blossoms, choosing paints that were beautiful in themselves without concern for how they behaved in mixtures with other paints. My approach to color became more integrated, and disciplined by an understanding of how the entire palette works together, rather than how pretty each color is in itself.
I'll summarize some of the tradeoffs among color and paint choices that the paint wheel highlights, to suggest how it can help you in your own color explorations.
Start with yellow. Best is a wide hue contrast, as these can mix any intermediate yellow without any loss in chroma. One yellow should be either absolutely neutral (neither red nor green), if not slightly green (lemon yellow); the other yellow should be far toward orange, without losing its basic yellow character.
You will come to appreciate the value of the siennas and ochres in this part of the color space: they anchor a specific muted yellow or orange, which can be adjusted by mixture with any other paint on the palette. Getting that muted mixture with saturated paints is harder than it might seem!
Good choices for light yellow are cadmium lemon or cadmium yellow pale; hansa yellow light, benzimida yellow, hansa yellow or green gold. The light yellow should produce greens that are bright yet natural across all the hues from green yellow to blue green. In that context I found bismuth yellow was too intense, and the various forms of nickel titanate yellow too dull.
Good choices for the orange yellow or yellow orange are cadmium yellow deep, hansa yellow deep, isoindolinone yellow. I found nickel dioxine yellow (PY153) gives very nice results. The deep yellow should be capable of mixing handsome greens with all the blue paints. If it produces a warm rather than greenish mixture with the blue violet (ultramarine), then your choice of deep yellow is too far toward orange.
Yellow is also the paint color that is fraught with many fugitive pigments, especially in the cheaper or lower quality brands of paint. Use the guide to watercolor pigments to check pigment lightfastness and avoid paints that contain impermanent pigments.
With two yellows, there are 10 slots remaining in the wheel.
Reds can be contrasted primarily on hue, chroma and to a lesser degree on lightness. There are few texture variations among red or crimson pigments, and nearly all red paints (other than the quinacridones) are at least partially opaque.
The red orange hue (next to the deep yellow) is only represented by a handful of pigments. A medium orange such as benzimidazolone orange is too similar to the deep yellow and tends to be too light valued. I found perinone orange (PO43) made interesting mixtures, but is not quite lightfast enough; and mixtures with pyrrole orange (PO73) are unexpectedly dull (diagnostic trick to remember: the orange shifts toward blue as you dilute it). All in all, cadmium red orange (PR108) is a very intense color, slightly lighter valued, and a beautiful mixer. (Winsor & Newton cadmium scarlet or Holbein cadmium red orange are closest to the most desirable hue.)
The paint you choose should produce handsome ochres and browns in mixtures with green paints, and should deliver a solid neutral gray in mixture with the complementary hue (teal blue).
There is a very large selection of red paints, and these divide into two types of red: the "spectrum" reds that contain no "blue" reflectance, and the "blue" reds that do provide "blue" reflectance, even when the paint color shows no blue tint (e.g., perylene maroon, PR179). Again, a useful diagnostic trick is to see whether the diluted tint of the paint seems to shift the color toward yellow ("spectrum" red) or toward violet ("blue" red).
If you choose a "spectrum" red, then violet mixtures will be quite dark, although the orange and yellow mixtures should be suitably saturated; however many "blue" reds mix quite saturated colors with a good yellow paint: note the mixture of quinacridone magenta and aureolin in the paint wheel shown at the top of this section. I think the choice therefore depends on whether you want to reproduce the violet mixtures you get with a blue red, or go for somber maroons and dusky violets with the "spectrum" red.
Back to the paint selection: cadmium red deep (PR108) is perhaps the best "spectrum" red choice, and quinacridone red (PR209) or quinacridone carmine (PR N/A) the best "blue" red. Vermilion or scarlet hues will be too close to the red orange, the lighter valued rose or carmine pigments will be too pink, and the brilliant pyrrole red (PR254), a blue red, is for me too strident. As with the yellow paints, the reds and violet reds are profuse with impermanent pigment choices, so make sure to use lightfast alternatives.
For the violet red (magenta), I don't believe there is a better choice than quinacridone magenta (PR122) it produces saturated mixtures on both the violet and the orange side though I often like the darker mixtures that quinacridone violet (PV19) can create. But quinacridone rose (PV19R) is an extremely flexible and beautiful color, though not quite as lightfast as the first two choices.
There is good separation in hue, lightness and chroma between cadmium red orange, quinacridone red and quinacridone magenta. But it is remarkably difficult to get real variety in warm color mixtures if you stick with saturated red, orange and yellow paints. The alternative is to choose a more muted paint (such as perylene maroon) for the "red" slot, and get a bright red by the mixture of quinacridone magenta and cadmium red orange.
The yellow orange red crimson magenta mixtures must generate effective contrast among themselves, pulling new color harmonies from all the others. If all these contrasts work, there will be a rich variety across all the left side color mixtures.
Two yellows and three reds leaves seven slots to fill.
The violet slot is either a red or a blue violet, and this biases the color mixtures in the lower half of the wheel. The pigment selections here are drastically limited, and many violet paints are in fact convenience mixtures of a magenta and violet blue.
In their working palettes, many artists omit a violet paint entirely, mixing all their violets from ultramarine blue and quinacridone rose or quinacridone magenta. It's useful to keep this alternative in mind, even though a paint wheel requires one violet pigment.
I have to recommend dioxazine violet (PV23) by default, for the blues it can pull all the way into the greens, and the deep browns it creates with the reds. Both cobalt violet deep or manganese violet are reasonable middle violet pigments, but each has a relatively weak tinting strength and an intriguing but sometimes assertive texture.
This fills six slots. The remaining six slots will be blues and greens.
There are many shades of green possible by mixing the blues with the two yellows, so one or two greens is enough (and in a working palette using no green at all is feasible).
If two greens, then the contrast can be in hue (one blue green and one yellow green), or in chroma and transparency (a phthalo green and a cobalt or chromium green). There are not a lot of attractive green pigments to choose from: viridian (PG18) is worth trying, though I found it too dull and weak in mixtures to suit my taste. The anhydrous yellow green alternative, chromium oxide green (PG17) has by contrast a high tinting strength, but is very dark and dull (though it works extremely well in diluted mixtures, due to its unique triple peak reflectance curve and powdery, cadmiumlike texture). The cobalt greens used to strike me as forbiddingly opaque, but I discovered that they can be poetic and flexible when used at higher dilutions and as part of an earth palette.
A reliable basic choice is phthalo green BS (PG7) for a blue green, phthalo green YS (PG36) for a middle green, and a convenience mixture labeled sap green or phthalo yellow green for the yellow green.
The point of using three greens is that the extent of green hues in the perceptual hue circle is in fact about 1/4 of the total circumference; and you will find that trying to match these green hues is actuall rather difficult. The difficulty will lead you to appreciate the many convenience greens, which, like the earth pigments, provide a stable and reliable green color that can be adjusted by mixture with any other paint on the palette.
This leaves three hues of blue to finish. As with green and violet, there is a rather limited pigment choice here: mostly cobalts and phthalos, with ultramarine blue and iron blue as the outliers.
The various shades of blue must mix well with both the yellows and the magentas, and this reinforces the point that the yellows and cool reds should also contrast and mix well together. (For example, quinacridone red and quinacridone magenta work well with aureolin and indian yellow.)
For a violet blue, it seems impossible to avoid the choice of either ultramarine blue (PB29) or cobalt blue (PB28). Look at your mixtures with yellow, red and magenta to decide between them: if you require bright violets and good tinting strength, then ultramarine is probably better. Cobalt blue is muted, but it can be stunning with other muted and transparent paints.
Phthalo blue GS (PB15:3), iron blue (PB27) or cerulean blue (PB35) are the principal choices for the middle blue paint. I prefer that this blue mix to a dark neutral with the red orange paint (spoke 3), yet make clean color mixtures with the warm yellow (spoke 2) and the red (spoke 4). This makes cerulean blue less desirable, though for some landscape or portrait palettes it can be essential, and its granulation is very evocative.
Finally, for the green blue, there are a handful of choices: cobalt turquoise, "marine" shades of phthalocyanine, or the marvelous manganese blue. I chose cobalt teal (PG50) because it produces a subtle granulation and lovely color in mixtures with every other paint on the wheel including a lustrous violet gray with quinacridone magenta. Manganese blue is less green a good choice if you like its strong granular texture. phthalo turquoise is quite dark and somewhat dull.
The blues must work well with the yellow green, the yellows, the red/orange, and the magentas. Typically almost any blue works fine with dioxazine violet, the greens, and all other blues.
The diagram below illustrates some basic points of the color landscape, as revealed in a paint wheel. These are the long spokes of the paint wheel shown below, aligned side by side. The top segment in each spoke is the pure paint color for each color point; the large middle segment was mixed by the adjacent pure paints on either side (which are 60° apart on the hue circle); the large bottom segment by the paints two steps on either side (which are 120° apart on the hue circle); and the short bottom segment by paints on opposite sides (180° apart on the hue circle).
variations in color mixture around the hue circle
The three additive "primary" hues orange red (R), blue violet (B) and green (G) reproduce quite well. In effect, subtractive mixture between any two randomly chosen paints tends to produce an orange, green or blue color.
The red additive primary combines poorly with both the blue and the green, producing two areas of dark color mixture around yellow (Y) and magenta (M). The reasons for this are not the same. The yellow darkening is due to the strong dependence of yellow appearance on high lightness (yellow reflectance, by itself, cannot produce a bright yellow color). The magenta darkening is caused by mixing two colors (blue violet and red) that are both at the darkened extremes of the spectrum (and therefore dark to begin with), and by using a "spectrum" red that reflects no "blue" light; it can be somewhat reduced by using a blue red (quinacridone red) instead.
The orange mixtures by contrast are neatly arranged by hue and chroma, in part because hue and lightness are closely associated in yellow to red hues (as colors shift from yellow to red, they become darker), and in part because the large variety of pigments available for these hues makes it easy to find pigments for almost any hue that have both high chroma and very compatible handling attributes (particle size, transparency, specific gravity).
In contrast, there is a great variety and something of a jumble among the green and blue mixtures, in part because there is no clear relationship between hue and lightness among the greens (blues become darker as their hue shifts toward violet), and because there is a much smaller range of blue or green pigments to choose from, which forces greater differences in lightness, chroma and handling attributes among these paints. This makes it much more difficult to match the green or blue hue mixed by one pair of paints with the color mixed by a different pair a challenge you will experience most clearly with the green mixtures, especially if you work with cobalt pigments.
The unsaturated color zones the dull colors that contrast so strongly with their hues (yellow, orange, red) that they have completely different color names appear as the greens underneath yellow, the brown underneath deep yellow, and then the browns and sepias in the short swatches under red orange and red. In other words, chroma has a very high visual impact on color mixtures in yellow, but the strength of this contrast weakens as the hue shifts into red.
The colors along the very bottom, all the way around the paint wheel, appear to be simply variations of black, brown or green. This illustrates the general principle that, as colors become more desaturated, the visual contrasts among them reduces to light vs. dark and warm vs. cool, which is visually often just the contrast brown vs. grue (green plus blue). Just as red, green and blue emerge across a wide span of mixtures, they anchor our sense of hue in colors close to gray.
These are among the most basic and important features of the color landscape using today's commercial paints. Understanding them will greatly increase your color mixing skills.
My color education is ongoing, so I'd like to close with the paint recommendations I'd make today for each of the 12 color points. (Contrast with the pigment locations in the artist's color wheel.) The mixing paint wheel shown below was painted with effort to match the hues within each spoke.
I mix my own phthalo yellow green as 1 part phthalo green YS and about 6 parts nickel dioxine yellow. I don't use the yellow paint anywhere else, so this mixture increases the color variety.
These 12 paints are probably not the best working palette and certainly not the optimal basic palette, both in terms of mixing convenience (no earth pigments) and paint lightfastness (depending on paint brand, the violet may fade). But it is a useful selection for exploring the varieties of hue, value range, texture, staining, tinting strength, transparency, handling attributes and mixing behavior of paints from all parts of the color wheel.
Whatever selection of paints you decide to use, paint wheels help clarify some fundamental features of the color mixing landscape: the difficulty of matching specific hues in green mixtures; the very dark mixtures produced by "spectrum" reds and blue paints; the dark mixtures produced by oranges and greens; the deep blacks produced by reds and greens; and so on. It also makes very evident the differences between pigments in hiding power and tinting strength, and the difficulty in judging color mixtures with cadmium or cobalt pigments and most synthetic organic pigments (the cadmiums and cobalts sink quickly out of a mixture, and to the bottom of a juicy paint layer, disguising their influence in the dried paint layer).
Finally, look over the mixed colors in your wheel and tally up the paints your mixtures appear to duplicate. For example, the wheel shown at the top of the page gives convincing substitutes for paints such as alizarin crimson, permanent green, thioindigo violet, cerulean blue, indanthrone blue, cadmium red, quinacridone maroon, raw umber, and hooker's green, among many others. These you could do without. By identifying the color location of these dispensible paints, you learn to reproduce the color at will from the actual paints on your palette.
The paint wheel helps you visualize the relationships among different paints, the tradeoffs in choosing one paint over another, and the paint combinations that create the widest and most attractive mixing possibilities.
Color is something you should explore for yourself by painting. It's really the only way to learn.