Mixing Metaphors
All colour mixed from three primaries. White and black are value modifiers only. Value is the most important quality of colour.
Value Scale
Each column shows a palette colour across 7 value levels. The ring marks its natural value. The curve shows the palette's tonal range.Ross Palette — Hot & Cold
After Denham Ross · The Painter's Palette · 1912. Two arrangements of the colour wheel across a value scale, built from the same primaries above.Green test — Yellow mixed with Blue
Subtractive mixing should produce a believable green at the midpoint.Colour Triangle — Maratta / Henri / Sloan
Outer: full intensity (A). Middle: semi-neutral / metaphoric primaries (B). Inner: neutral (C). System originated by Hardesty Maratta, transmitted by Robert Henri, taught by John Sloan.Select Primary Paint
Paint-like mixing
Controls how physically realistic colour mixing is, on a scale from perceptual blending to pigment simulation.
0% — OKLab blend: Colours mix through a perceptually uniform colour space. Transitions are smooth and even, but yellow + blue gives a muddy neutral — not green.
100% — Mixbox (Kubelka–Munk): Simulates real pigment behaviour. Yellow + blue gives green, red + blue gives violet — matching physical paint.
Default 85% blends both modes: paint-like hue results with smooth tonal transitions across the value table.
The Maratta / Henri / Sloan Colour Triangle
The lineage
Hardesty Maratta (1864–1924) was a Chicago-based colorist who developed a rigorous pigment-mixing system organised around the RYB wheel and structured by value levels. His system became the foundation for how a generation of American painters understood colour.
Robert Henri (1865–1929) — painter, teacher, and central figure of the Ashcan School — studied Maratta's palette closely, corresponded with him extensively, and taught from his colour framework. Henri's influence on his students was profound. His teachings are collected in The Art Spirit (1923). The connection is documented by painter and scholar Judith Reyes in The Color Investigations of Robert Henri, Vol. 2, p. 96.
John Sloan (1871–1951) was Henri's close friend and student. He absorbed the Maratta/Henri colour system and taught it widely, publishing it in his 1939 book Gist of Art. The colour triangle became Sloan's most enduring teaching device — which is why his name has traditionally been attached to it.
"The beginner is always asking, what colour shall I use? The real question is, what value shall I use?" — John Sloan
The theory: neutralisation in three steps
The system organises all colour into three concentric tiers, each representing a step of neutralisation away from full pigment intensity. Moving inward on the triangle means mixing a colour progressively with its complement until it approaches a neutral grey.
Reading the triangle
Yellow sits at the top, Red at lower-left, Blue at lower-right — matching the traditional RYB wheel. Twelve circles around each tier mark the twelve hues: R, RO, O, YO, Y, YG, G, BG, B, BV, V, RV. Thin web lines connect each hue position across tiers, showing the neutralisation path inward.
When mixing, think of it as a map: picking a colour means choosing both a position (hue) and a tier (intensity). Moving inward adds complement. Moving along a tier keeps intensity the same but shifts hue.
Value above all
The system's deepest lesson is not about colour at all. Value — the lightness or darkness of a colour — is the single most important quality in a painting. Colours that are correct in value but wrong in hue will still read. Colours correct in hue but wrong in value will look wrong. The value scale in this app illustrates exactly this: each hue family spread from light to dark, with a ring marking where each colour naturally sits.
In this app
The three palette tiers are computed by mixing your A primaries with their complements to derive new B and C primaries, then building full 12-hue wheels from each set. Hover any circle on the triangle for its exact hex value. Export swatches to Illustrator or SVG for physical mixing reference.