Oil Paint Color Mixer

About this tool

This is a mixing calculator first. You say how much of each paint goes onto the palette, and it gives you back the proportions, the volume and the color written out in the codes a studio actually uses. Amounts are held as a share of one full pile: 100% is the whole pile and one whole pile is 5 mL, which is roughly what comes out of a 37 ml tube in six squeezes. Switch the unit and every field converts with it — 50% becomes 2.50 mL becomes 0.169 fl oz for the total — so the same recipe works as a ratio when you are mixing on a palette and as a measurement when you are batching a color for a large canvas and need it to come out the same tomorrow.

The default mix is the amount-weighted average of the paints you set, and it is deliberately simple: it is the arithmetic of the recipe itself, so half white and half red is exactly halfway between them, and doubling everything changes the volume without touching the color. That predictability is the point of a calculator. The readouts follow from it — HEX and RGB straight from the mixed value, CMYK derived from those, and a Pantone-shaped code that is an approximation of the hex rather than a licensed ink, which is why it says approx. on the label.

Real paint is less obedient, and that is what the Realistic pigment mixing switch is for. A screen makes color by adding light; pigment does the opposite, absorbing part of the spectrum and scattering back only what every particle in the pile failed to absorb. Average Cadmium Yellow and Ultramarine on screen and you get a dull olive; mix them in oil and you get a green, because yellow eats the blue end, blue eats the red end, and the green band survives them both. The switch models that with a single-constant Kubelka–Munk approximation on linear RGB — an approximation, not a spectral simulation, so use it to decide which two tubes to reach for and mix a test patch before you commit a large passage.

The other thing a palette teaches is bias. No pigment is a pure primary: Ultramarine leans red, Phthalo Blue leans green, Cadmium Red Light leans orange, Alizarin Crimson leans violet. Mix two that lean away from each other and between them they absorb nearly the whole spectrum, which is what mud actually is. Which is the argument for a limited palette — six or seven tubes, one warm and one cool version of each primary, mixed constantly and compared against the subject. It is the discipline behind every studio copy of an old master, and most of what actually happens when an oil painting reproduction is made by hand. Adding a twentieth tube rarely fixes a color problem; working out which two you already own are fighting each other usually does.