Craft

The Iznik palette.

Q: How does the studio apply the Iznik palette?

Not by painting colour on by hand. The engine groups the faces of a pattern by congruence class - which faces are the same shape in the same orientation - and assigns one glaze to each class, following the zellige rule that no two touching faces share a colour. The Iznik palette is one such assignment: cobalt, turquoise, bole red and sage mapped onto the classes of the geometry. Change the four colours and the whole pattern re-glazes at once, because the colour is bound to the geometry, not to the individual tile.

Four glazes and a white ground made the most recognisable colour scheme in Islamic ceramics. Two blues, a green, and a red no other kiln could hold. Here is where each came from, and how the studio puts them onto a pattern - not by taste, but by a rule the geometry itself decides.

FIG. 1 - The four glazes on a ten-fold field, drawn live. Cobalt, turquoise, the bole red and a sage green on a white ground, one hue to a congruence class.

Four colours and a white

The ground comes first, and it is not a colour but an absence of one: a clean white slip laid over the pale fritware body, the surface everything else is painted on. Onto it, in order through the sixteenth century, came the blues. Cobalt was there from the start, the deep blue of the earliest blue-and-white. Turquoise, a lighter copper-based blue, joined it, and a sage green after. For a while there was a manganese purple too. By the middle of the century a painter had blue, green and white to hand. What was missing was the colour the name Iznik now conjures.

The red that stood up

Around 1560 the Iznik potters solved a hard problem. They found how to fire a thick, iron-rich red - made from an ochre clay called Armenian bole - so that it held its colour under the glaze and sat very slightly proud of the surface, catching the light where the other colours lie flat. That raised sealing-wax red is the signature of the best Iznik work and the hardest thing in the palette to get right. When the kilns declined in the seventeenth century, it is the first colour to go: the same red fires dull and brown, and you can date the slide by it.

FIG. 2 - The same four glazes on cut-tile work: cobalt ground, turquoise tiles and the bole red on the hook-shaped pieces.

Colour by class, not by hand

Here is where the studio parts company with a painter. It does not choose a colour for each tile. It groups the faces of a pattern by congruence class - which faces are the same shape in the same orientation - and gives one glaze to each class, under the old zellige rule that no two faces which touch may share a colour. The Iznik palette is one such assignment: cobalt, turquoise, bole and sage mapped onto the classes of the geometry. Because the colour is bound to the geometry and not to the individual tile, changing the four glazes re-glazes the whole wall at once, and the pattern stays legible because the rule that kept neighbours apart still holds.

THE PALETTE, IN ONE SENTENCE - four glazes on a white slip, cobalt and turquoise, a sage green and the raised bole red of about 1560, applied not tile by tile but one glaze to each congruence class, so the colour belongs to the geometry.

Your own glaze

The Iznik quartet is one palette among many the studio ships, and one you can change. Swap the four colours for a Fez register, a marble one, or your own, and the assignment holds: the geometry decides which face takes which slot, you decide what fills the slot. Then it exports - as print-ready SVG, a seamless repeat tile, or a fabrication file that carries the colour grouping through to the cut list. The blue is historical; the way it lands on the pattern is a rule you can watch work.

Read on

What is zellige? Morocco's cut-tile mosaic, explained The craft the colour rule comes from - hand-cut glazed tile, the Fes palette, and the seven-century convention that no two touching pieces share a colour.

Recolour a pattern in the Iznik palette.

Load the four glazes, watch the geometry assign them by class, then swap them for your own and export - free to explore in the browser.

Open the studio

Common questions

What colours are used in Iznik pottery?

The classic Iznik palette is four glazes on a white slip ground: a deep cobalt blue and a lighter turquoise, a sage or emerald green, and a thick tomato-to-sealing-wax red. Earlier wares are blue-and-white only, or add a manganese purple; the full four-colour palette belongs to roughly 1560 to 1600, the high period of the kilns.

What is Armenian bole red?

Armenian bole is an iron-rich clay, and the name is used for the signature Iznik red made from it: a thick, slightly raised red the potters learned to fire around 1560 so it sat proud of the surface and held its colour under the glaze. It was technically difficult and is one of the marks of the best Iznik work; on later, declining wares the same red often fires duller and browner.

How does the studio apply the Iznik palette?

Not by painting colour on by hand. The engine groups a pattern's faces by congruence class and assigns one glaze to each class, following the zellige rule that no two touching faces share a colour. The Iznik palette is one such assignment; change the four colours and the whole pattern re-glazes at once, because the colour is bound to the geometry, not to the individual tile.