Research

Mixing on the palette

The owner asked twice. First: "I expect that when I touch colour in the palette I can pick it up to mix." Then: "Please investigate how real artists mix colours on a palette, and the best ways to do that." The pigment model already mixes like paint (Mixing). This report is about the handling: what painters do with their hands and tools between tube and canvas, and which parts of it a fingertip on glass can carry.

How painters actually mix

1. The palette is laid out the same way every time. Colours go around the edge in a fixed order, usually warm to cool, with white in its own place. The middle is left open for mixing, on the side nearest the painter. A consistent layout makes mixing faster and judgement more intuitive, because the hand learns where each colour is. Schmid's colour charts train exactly this: every palette colour mixed with every other, and each stepped with white into five values. (Draw Paint Academy on Schmid's charts, methods.art on Reilly's organised palette) → The app already does this. Blobs sit along the top edge of the dish in a fixed order, the open porcelain below is the mixing area, and blobs refill in place.

2. Paint is brought from the pile to the mixing area. The pile itself stays clean. A painter takes a little from the edge of a blob with a knife or a clean brush and carries it to the middle. A dirty brush pushed into a pile contaminates it, and "a dirty brush makes mud." (Old Masters Academy: basic rules, ZenART mixing guide) → In the app: a tap takes colour from a blob without dirtying the blob, a forgiving version of the rule. A drag from a blob carries a lump into the open glass and leaves it where you lift, which is exactly the carrying motion.

3. Strong into weak, a little at a time. Dark and high-tinting pigments overpower light ones. So painters start with the light, weak colour (usually white) and add the dark in small amounts, never the reverse. (Naturalist Gallery: mixing tips, Color2OilPaint: 4 rules) → This is where a fixed-size dip falls short. Every tap picks up about the same amount, so white-then-red gives a half-and-half pink, not "a touch of red in white." Contact size already helps: a light fingertip takes a little and a flat press takes a lot. Proposed: make the amount a tap adds depend on how long the finger rests. A quick touch takes a trace, a longer press loads more, and a ring around the finger shows it filling. That's the "little at a time" gesture.

4. The knife mixes thoroughly; the brush mixes partly, on purpose. A palette knife presses, spreads and folds paint until the mix is even. It's precise with amounts and can't overblend. A brush stirring on the palette, or two colours picked up together, gives a partial mix. Painters use that deliberately: a stroke of "broken" colour with streaks of each pigment is livelier than an even mix. (Milan Art Institute on knives, Fine Art Tutorials) → The app has both. A drag on the palette is a knife fold, and it mixes thoroughly. Two taps load the brush with both colours. The bristles then carry them unevenly, so the start of a stroke shows streaks that blend as the brush empties, like a real loaded brush. Rebelle models the same thing: several colours picked onto the tip start a stroke separately and then mix toward their average (Rebelle manual: mixing palette).

5. Premix strings of values. Reilly's students premixed a nine-step grey scale and matching value strings of their main colours before painting. That gave them absolute control of value and no remixing mid-painting. (Wikipedia: Frank J. Reilly, Gurney Journey: prismatic palette) → Proposed "string" gesture: drag from a colour blob to the white blob and release, and the app lays five graded piles, from pure colour to a pale tint, along the empty glass. It's one gesture for a job that takes a painter minutes, and each pile is then a tap to load.

6. Mix more than you think, and test it before committing. Rematching a mix is hard, so painters mix generously. They also test a mix by dabbing it at the canvas edge, or by holding the knife up against the subject. → The app mixes generously by design: blobs are large and refill. Testing is free, since a swatch on the canvas is just a stroke. A future idea: a "test strip" margin.

7. Few pigments, few at a time. More than three pigments in one mix drifts to mud. Limited palettes (Zorn's white, ochre, vermilion and black) harmonise because every mix shares parents. → The six pigments already form a limited palette. The hint names what's on the brush ("Ultram. + Cad yel"), which makes a four-pigment mud visible before it's painted.

8. The canvas is a palette too. Painters also mix wet-into-wet on the canvas, pulling one colour into another with the knife or brush. (Fine Art Tutorials) → Already built: wet paint on the board mixes under every tool, through the same pigment model.

How other apps handle it

• Rebelle has a separate mixing-palette panel with pigment-based mixing (Mixbox). You pick colours up from it with a colour-pick tool, and you can load several colours onto the tip, which then mix along the stroke. (Rebelle manual, Mixbox)
• ArtRage mixes paint on the canvas with oil and palette-knife tools, has an optional "Real Color Blending" mode (so blue and yellow make green), and uses a Color Sampler tool to pick colours up. (ArtRage blending, ArtRage iPad colours)
• Mixbox is the Kubelka–Munk colour-mixing library behind Rebelle Pigments. It's the same physics as Enogu's model, packaged as RGB in and RGB out. (80.lv on Mixbox)

The pattern and the gap: these apps treat the palette as a colour picker. You sample a colour from it, and a separate mode or tool is needed to mix. None found makes the palette a physical surface where the same finger carries, folds and dips paint with no mode switch. That's Enogu's opening: tap to dip, drag to carry and fold, with real piles on a real dish.

Recommendations, in order

1. Keep the two gestures. Tap to dip (adding to what the tool carries) and drag to carry and fold. They match what painters do with a brush and a knife, and need no mode.
2. Dwell sets the amount of a dip: a quick touch for a trace, a longer press for a full load, with a filling ring. This gives "a little at a time" without a slider.
3. Value strings: drag a colour onto white to lay a graded string of five piles.
4. Tint preview: while a finger rests on a pile, show a small swatch of what the brush will carry after the dip. That's what painters get by looking at the mix on their brush.
5. Keep blobs clean (a dip never contaminates the pile), but let mixes on the glass be contaminated by whatever the knife drags through, as on a real palette.

What changed in the app

• 2026-09-26: a tap now adds to what the tool already carries (finding 4), and Clean in the dock starts it fresh.
• Proposed: recommendations 2–4, on the task list.