The colour card

Three oxides. Eleven colours. One rule.

Every colourway we fire is a measured mix of the same three metal oxides over the frit white — and it is mixed by subtraction, not addition, which is why it behaves the way it does.

Iron

gives red

Cobalt

gives blue

Copper

gives green

How the range is made

Eleven colours, three oxides, one rule.

Enamel takes its colour from metal oxides fired into the glass — iron for red, cobalt for blue, copper for green. Pigment mixes by subtraction: the reflectances multiply, so stacking oxides only ever removes light. That is why the middle of the card is mud, and why the frit with nothing in it is white.

Iron Red
subtractive · the glaze C* —
additive · screen (control) C* —

Scroll to mix the pots.

The full card

Two of the eleven are references, not products. Frit is the bare base with no oxide, so it is white. Ash is all three oxides at once — the mud every mix leans toward if you are not careful.

Frit no oxide — the bare frit reference · the base
Ember iron, half charge
Iron Red iron, full charge
Damson iron + cobalt
Cobalt cobalt, full charge
Chalk Blue cobalt, part charge
Peacock cobalt + copper
Verdigris copper, full charge
Sage copper, part charge
Moss iron + copper
Ash iron + cobalt + copper — the mud reference · the mud

Why the screen lies

A screen adds light; a glaze removes it. Mix two oxides on a monitor and you get a bright average — mix them in the kiln and the reflectances multiply, so complementary oxides cancel to grey. Here is the same mix both ways, measured as chroma (C*, higher is more colourful):

ColourwaySubtractive · firedAdditive · screen
Damson 21 45 oxides fight → mud
Peacock 24 24 neighbours agree
Moss 9 26 oxides fight → mud
Ash 9 21 oxides fight → mud

Computed from the mixing model this page's canvas runs; the eleven card values are guarded against drift by scripts/card.mjs --check.