Split complementary takes a color and, instead of its opposite, the two colors either side of that opposite: 150° and 210° round the painter's wheel. From red, that is yellow-green and blue-green; from yellow, blue-violet and red-violet. It keeps most of the contrast of a complementary pair with less of the clash.
What it does
Press “Split” under “Harmonies”. Its diagram is a Y: the base color on a stem, and the two split colors splayed below it, either side of where the opposite would be.
With a color locked, that color stays put. The next card in the order Front, Back, Ground is turned 150° around the wheel, and the card after it 210°, both keeping the locked color's saturation and lightness. Around the wheel means in the direction red, orange, yellow, green.
- Front locked: the Back at 150°, the Ground at 210°.
- Back locked: the Ground at 150°, the Front at 210°.
- Ground locked: the Front at 150°, the Back at 210°.
With nothing locked, the selected card gets a random hue and the other two land at 150° and 210° from it, with saturation and brightness drawn at random and the ground kept pale.
Split has no step of lightness. Locked, all three colors share one lightness, so the contrast of light and dark a notan runs on is yours to add. Change any color's brightness and the harmony stays armed without touching the other two.
This is one of the two lopsided harmonies (analogous is the other): its three colors are not interchangeable. The base stands alone, and the two split colors are only 60° apart, close cousins. While it is armed, dragging any one color's hue turns the whole Y as one piece, so each color keeps its part.
Why it works this way
A complementary pair is the strongest contrast of hue, and for some designs too strong: two colors in a stand-off. Splitting the opposite into its two neighbors keeps the tension between the base and the far side of the wheel, but spreads it across two colors that are near each other. The eye reads one color against a family rather than one against one.
In a notan that shape fits the three roles well. With the Front locked, the back and the ground take the two split colors. Each flip is the front against one neighbor of its opposite; the ground is the other neighbor, related to the flips but not the same. The folds carry the contrast, and the ground quietly agrees with the flips.
The 30° either side is not arbitrary. On a twelve-step painter's wheel, the kind Itten drew, 30° is exactly one step: the split colors are the complement's immediate neighbors. Seen that way, three of the five harmonies are one family. Put the base at the tip of an isosceles triangle and swing the two other corners: 30° either side gives analogous, 120° gives a triad, 150° gives a split, and at 180° the two corners meet and you have a complementary pair.
The metaphor
“Split” pictures the opposite color broken in two, like a path forking around an obstacle or a beam divided by a prism. The diagram draws exactly that: a stem, then a fork.
The picture holds as geometry and loosens as perception. The two branches are equal on the diagram, 30° each side, but equal angles on a wheel are not equal differences to the eye. The painter's wheel that Studio Notan uses gives the warm half of the circle, red around to green, 180°, where a screen gives it 120°. So a step of 30° among the warm hues is a smaller change of screen hue than a step of 30° among the cool ones. From red, for example, the app's split lands on a yellow-green and a blue-green close to cyan; the same rule worked on the screen's own wheel would give a spring green and an azure. The two split colors also often differ in how light and how strong they look. The fork is symmetrical on paper and lopsided in the eye, which is one reason to adjust by eye once the harmony has done its work.
A history
In art
Nobody seems sure who first called this harmony “split complementary”. It is a classroom name, and it names an arrangement more than a tradition: painters did not set out to paint split complements so much as teachers found the shape afterwards in pictures that worked. Look and you will see it everywhere: a figure in orange against a sky that runs from blue-green to blue-violet is a split complement of orange, whatever the painter called it. Crediting any particular painter with intending one would be inventing history.
The idea behind the name is on firmer ground. Johannes Itten, whose The Art of Color (1961) collected his Bauhaus teaching, counted as harmonious not only the evenly spaced triad but any three colors forming an isosceles triangle on his twelve-part circle. The split complement is one of those triangles, the one whose short side straddles the complement. In Itten's terms it is a triad, a sibling of the evenly spaced one.
In printing
Printing has no split-complementary tradition of its own. What it has is the reason a three-color rule matters. A three-color screen print or letterpress job needs three stencils or plates, each inked, registered and pulled separately, and it cannot afford three colors that fight or three that blur together. A rule that promises strong contrast from exactly three inks is worth a great deal to anyone paying per color.
Printing did give the harmony rules one of their most familiar objects: the printed color wheel with a turning disc, sold in art shops, where you set a pointer on a color and cut-out windows show its complement, its split, its triad. The turning paper disc is an old printed device. Books of astronomy were printing them centuries earlier: Peter Apian's Astronomicum Caesareum of 1540 is famous for its layered, rotating paper discs. A harmony dial is the same paper computer, set to a gentler problem.
In technology
Software made the split a menu item. Adobe Color, which began in 2006 as Kuler, lists “Split Complementary” among its harmony rules, alongside a “Double Split Complementary”. In tools like it you drag the base color and the others follow at fixed angles, which is the same rigid turning Studio Notan does while a harmony is armed.
Studio Notan learned the value of that rigidity the hard way. An earlier version rebuilt the harmony round whichever color you grabbed. For an evenly spaced triad that made no difference, but for a split it did: grab a split color and the harmony was rebuilt with that color as the base, the other two jumped to new hues, and it looked as though the swatches had swapped places. Now the whole shape turns by the amount you turned one corner, measured on the paint wheel, and nothing jumps.
In professional software
The split complement goes by the same name almost everywhere. Designers reach for it when a complementary pair is too loud: it keeps a strong accent while giving the palette a second supporting color.
- Adobe Color. Choose ‘Split Complementary’ and drag the base color around the wheel: the two split colors keep their fork on the far side, as they do here while the harmony is armed. The wheel is a painter’s wheel, like this one.
- Adobe Illustrator. The ‘Color Guide’ has ‘Split Complementary’, 30° either side of the opposite, and two lopsided cousins, ‘Left Complement’ and ‘Right Complement’, that bend the opposite one way only. A button at the foot of the panel limits the harmony to a swatch library, such as a spot-color book, so the three colors arrive as inks a printer can match.
- Procreate. ‘Split Complementary’ in the ‘Harmony’ tab shows three reticles: your color and two either side of its opposite. Tap any of them to paint with it.
What carries over. In a brand palette the base is usually the lead color and the split pair become its supporting colors, one for large areas and one for small accents. That division of labor is the useful habit: decide which color leads before you decide the hues. The pitfall is lightness. The two split colors are the same distance around the wheel but rarely look equally light or strong, so look at the palette in grayscale before you commit, and nudge brightness until the order of light and dark is the one you intended.
Try this
- Lock the Front, give it a strong yellow, and press “Split”. The back turns blue-violet and the ground red-violet. Cut and flip a shape.
- Drag the Back swatch onto the Ground card, so the flips wear the other split color, and compare.
- Lower the ground's saturation until it becomes a quiet partner to the flips rather than a rival.
Going further
- Complementary is the harmony this one softens; Triadic is its evenly spaced sibling; Color harmonies explains all five.
- Colors explains swapping two colors by dragging a swatch.
- Books: Johannes Itten, The Art of Color; Josef Albers, Interaction of Color.