The mathematics

Ottoman ceramic borders.

On an Ottoman tile wall the flowers take the eye. But a field of flowers is always framed, and the frame is not decoration added at the end - it is geometry, and it is doing the structural work. A running border of stars and crosses, a chain of cartouches, a band that steps inward course by course. This is how the frame is built.

FIG. 1 - Border courses, drawn live. A twelve-fold field stepped into concentric bands, each course an inward offset of the one outside it, in a turquoise-on-white Iznik register.

The frame does the work

Think of an Ottoman tile panel as two parts: a field and a border. The field is the large repeating pattern in the middle, often the floral one. The border is the narrow run around it. It is the border that sets the scale of the field, squares it to the architecture and carries the eye around the four sides, and unlike the field it has to solve a specific problem - it has to turn the corner and still read as one continuous thing. That is a geometric problem, and Ottoman tilework solves it geometrically: a star-and-cross unit, a knot, a chain of cartouches, repeated along the run and reflected at the corner.

Courses: a band as an inward step

There is a second kind of border, and it is the one in FIG. 1. Instead of a separate motif, you take the field pattern itself and offset its faces inward, a fixed step at a time. Each step gives a new course, a shrunk copy of the pattern sitting inside the last, so the panel reads as a set of concentric rings of the same geometry. In the studio these are the band courses: literally inward offsets of the field, which is why the border and the field are so obviously related. They are not two patterns. They are one pattern at several scales.

FIG. 2 - The field a border holds. The octagon-and-square, one of the most common Ottoman geometric panels, glazed in the four Iznik colours.

The field the border holds

FIG. 2 is the kind of field a border is built around: the octagon-and-square, an eight-fold tessellation that recurs across Ottoman and wider Islamic tilework because it tiles the plane with only two simple shapes and takes colour cleanly. Set a running border around a field like this and you have the basic grammar of a tiled wall: a legible centre, a frame that scales and squares it, and a join that closes. The studio can draw the field on its own, or place it inside its frame.

The composed panel

Put the two together and you get a dado panel: a field course seated between two friezes, divided by the thin lines a tile-setter calls listels. The dado is the lower band of a wall, and the dado panel is the standard composed unit for it across Islamic tilework. The studio composes one directly - you choose the field pattern, the frieze that frames it, and the share of the height each takes - and exports the whole thing as one drawing, ready to hand to a fabricator. The two figures on this page are the field and the courses that make up such a panel; the composed panel itself is what the export writes, and what the Iznik series posts as a single plate.

A BORDER, IN ONE SENTENCE - not decoration laid over a field but the same geometry stepped inward or repeated along a run, the part of a tile panel that sets its scale, squares it to the wall and turns the corner.

Read on

The Iznik palette: cobalt, turquoise, bole red and sage The four glazes that colour these panels, where they came from, and how the studio lays them on by congruence class.

Compose a bordered panel.

Set a field between two friezes, choose the band courses, recolour by class and export the whole panel as one file - free to explore in the browser.

Open the studio

Common questions

What are Ottoman ceramic border tiles?

Border tiles are the narrow runs of tile that frame a larger field on an Ottoman wall. Where the field is often floral, the border is frequently geometric: a running band of stars and crosses, a chain of cartouches, or a knot that repeats and turns the corner. The border organises the wall, sets the scale of the field and carries the eye around it, the same job a picture frame does.

How is a geometric tile border constructed?

A running border is a one-dimensional repeat: a single motif translated along the band and reflected to turn the corner. Concentric borders are built by offsetting a pattern's faces inward step by step, so each course is a shrunk copy of the one outside it. In the studio the band courses are inward face offsets of the field itself, so the border and the field it frames are visibly the same geometry at two scales.

What is a dado panel?

The dado is the lower part of a wall, and a dado panel is a composed unit of tilework for it: a field course seated between two friezes, separated by thin dividing lines called listels. It is the standard way Islamic tilework frames a field. The studio composes a dado panel directly and exports the whole panel as one drawing.