Azulejos: Spanish tiles, their rules, and a workshop to build your own

The tile in the corner of every page of this site is Valencian: a flower in the middle, quarter circles in the corners. On its own it is modest. Put four side by side and the quarters close into whole circles. That is the whole secret of the azulejo: the pattern lives not on the tile but on the wall.

The word comes from Arabic: az-zulayj, "polished little stone". It has nothing to do with azul ("blue"), though the coincidence is a happy one: cobalt blue runs through the whole history of Spanish tiles.

In Spain an azulejo is not a museum rarity. It is the dado in a bar, a street-name plaque, a grandmother's kitchen, a bench in a square. Below is how it works. If you would rather build a wall straight away, the workshop is at the end.

The main rule: glazes must not mix

A tile is coated with glaze, coloured glass in powder, and fired. In the kiln the glaze melts and runs. Put blue next to green and after firing the border between them blurs into a muddy brown seam. Almost every Spanish technique answers one question: how do you keep the colours apart? You recognise a technique by its answer.

Alicatado: cut, don't paint (14th–15th centuries)

The most radical answer: no tile carries two colours at all. The craftsman fires single-colour tiles, then cuts them into pieces with a chisel and sets them as a mosaic, like a puzzle. The kiln is already behind him; everything depends on the cutter's hand. This is how the 14th-century walls of the Alhambra in Granada and Pedro I's Mudéjar palace in the Alcázar of Seville were made.

Hence the geometry: eight-pointed stars, polygons, and bands that weave "over and under" (lazo, "bow, loop"). Curved pieces were rarely cut and were the hardest work of all. A star of straight lines on a grid is far easier to cut.

Cuerda seca: the "dry cord" (on tiles, 15th–16th centuries)

Cutting is slow and costly. The answer is old — al-Andalus knew it as early as the 10th century — and in the 15th century Seville and Toledo brought it to tiles: draw the outline with manganese mixed with grease. The grease repels the glaze, so each colour stays in its own cell. After firing the outline stays a dark matte line, brown or almost black, around every patch. You spot it at once; it is the signature of the technique.

Arista: a ridge of clay (from the late 15th century)

Faster still: the design is pressed into wet clay with a mould. Thin ridges (aristas) stay between the cells, and the glaze cannot cross them. The ridges are glazed too, only thinly, so in the light they read a little paler than the cells. One mould, thousands of identical tiles. Seville's tile-makers made so many that they shipped them abroad: in 1508–09 King Manuel I of Portugal ordered about ten thousand tiles from Seville for the palace at Sintra.

Pincel: a brush on white enamel (from the 1490s)

By 1498 an Italian, Francesco Niculoso, known as Pisano, was living in Triana, Seville. He brought maiolica: the tile is coated with raw white tin enamel and painted with a brush, like a fresco. Separators are no longer needed, because the colours sink into the enamel and do not run. Pictures made of tiles appear: altarpieces, coats of arms, scenes. His altarpiece in the chapel of the Alcázar is signed and dated 1504. The enamel need not be white: in Faenza, Italy, painters also worked on a blue one (berettino), only in light colours, for contrast.

Talavera de la Reina took the technique further. Its palette changed with the period: from the late 16th to the mid-17th century the "three-colour" series (blue, iron orange and manganese for outlines), while animals, flowers and hunters are often painted in blue alone on white. In 2019 the ceramics of Talavera and El Puente del Arzobispo, together with the Mexican "talavera" of Puebla and Tlaxcala, were inscribed on UNESCO's list of intangible heritage.

Chemistry sets the palette

A glaze gets its colour from a metal. So every period has its own short set, and that set is what makes a pattern look Spanish:

In the workshop below the palettes are split by period: 15th-century Mudéjar, 17th-century Talavera, 19th-century Valencia, and the blue-and-white tile of the 18th century. Change the period and you only get its glazes.

One tile, many patterns

The flower on this site is symmetric: turn it any way and it stays the same. Tiles like this are laid "all the same" (todas iguales), and the result is a carpet.

Valencia in the 17th and 18th centuries had a clever tile, the mocadoret, "little kerchief" (also called de mitadat and de cartabón, "set square"; in the workshop we use the Castilian pañuelo). It is split along the diagonal, one half coloured and the other white. On its own it means almost nothing, but once you turn it, a pattern appears. Turn four tiles with their coloured corners towards a shared centre and you get a diamond (in the workshop this option is «Hacia el centro», "towards the centre"). Turn them round with a shift and you get a pinwheel (in the workshop we call it molinillo, "little mill"; that is our word, not a trade term). Turn every other row and you get a zigzag "ear of wheat" (espiga, also the word for herringbone parquet or tiling).

All of this is the mathematics of symmetry. In the ornaments of the Alhambra you can find most of the 17 possible symmetry types of a flat pattern: a 1944 count found 12, later ones more, and whether all 17 are there is still argued over by mathematicians. The craftsmen knew no group theory, but they knew what a turn does.

The wall: dado, border, whitewash

In Spain tiles very often cover not the whole wall but its bottom: the zócalo (dado), up to about shoulder height. A border, the cenefa, closes it at the top, and above that the wall is whitewashed with lime. The dado protects the wall from damp, chairs and shoulders, it is easy to wash, and it keeps the room cool in summer. In the workshop this option is called zócalo.

On floors you will often see the olambrilla, a small coloured tile, about seven centimetres across, set between large terracotta ones. It is found in Andalusia, but also in Toledo, Aragon, Catalonia and Valencia. Same logic: little colour, a lot of rhythm.

Map and time

Where and when it happened. Tap a year or a city: the place lights up on the map, and next to it a tile of that time appears, with where to see it today. Look at the rivers too: Toledo and Talavera stand on the Tajo, and Seville is a river port on the Guadalquivir, about 80 km from the sea. Granada lies at the foot of the Sierra Nevada.

And Portugal?

The technique reached Portugal from Seville: in the early 16th century Sevillian arista tiles were shipped there (the palace at Sintra is tiled with them). Then the paths split. Portugal made the azulejo a national art: huge blue-and-white Baroque narrative panels, and later tiled façades. Spain held on longer to Mudéjar geometry and many colours. That is the broad picture, not a strict rule: there are exceptions both ways.

The workshop

Here you can build a wall by the rules of this article. Paint the big tile: every tap on one of its parts takes the next glaze of the period. Choose a technique: it decides how the colours are kept apart. Until the tiles are fired the glaze is a chalk-white powder with grey and brown colours on it, and the real colours only come out in the kiln (¡Al horno!). Try the sin separar ("without separating") technique and see what the kiln does to glazes that nothing holds in place. And in the workshop alicatado is only for the star: curves were hardly ever cut.

Tiles can be turned right on the wall: tap a tile and it turns a quarter. With the symmetric flower this changes nothing; with the kerchief and the quarter it changes everything. You can download the finished wall as an SVG. The tools open as you read: each «Hazlo tú» block above opens its own (and if you are in a hurry, press «Abrir todo»).

A small glossary

Try describing your wall in one sentence: Mi zócalo tiene piezas de mocadoret giradas hacia el centro, con esmaltes de Valencia. — "My dado has pieces of little kerchief turned towards the centre, with glazes of Valencia."