How Byzantine Icons Were Made

An icon is a manufactured object before it is a holy one, and the manufacture was highly standardised. A painter in eleventh-century Constantinople, a monk on Sinai in the fourteenth century and a Russian workshop in the sixteenth used substantially the same materials in substantially the same sequence. That conservatism is the reason icons of very different dates can look so similar, and it is also the reason a well-made icon survives: the technique is one of the most durable ever devised for painting on wood.

The theology behind the practice is treated in the theology of icon veneration and the visual conventions in Byzantine iconography. What follows is the craft.

The Panel

Byzantine panels are usually of a light, stable hardwood — poplar and lime in the Greek world and Italy, cypress in the eastern Mediterranean, pine where nothing better was available. The wood was seasoned, and boards were joined edge to edge with dowels and glue for larger images.

Two features distinguish a Byzantine panel from a plain board:

Battens. Slats let into grooves across the back, running against the grain, to restrain warping. On a well-made panel they slide rather than being fixed rigidly, allowing the wood to move with humidity.

The recessed field. Most icons are carved out so that the painted surface sits a centimetre or so below a raised border. This is not only decorative. The raised edge protects the paint surface from abrasion, and it frames the image in a way that was understood to mark it off as a window rather than a picture.

Behind both of these is the practical fact that panels split. A large proportion of surviving icons show old repairs along joins, and the raised border frequently does not.

Ground and Canvas

Over the wood the painter glued a layer of fine linen — the practice appears in Byzantine panels from the earliest surviving examples — using animal-skin glue. The cloth bridges the joins between boards and any small splits, so a crack in the wood does not automatically become a crack in the paint.

Onto the linen went the ground: gesso, a mixture of animal glue with chalk or gypsum, applied warm in many thin coats, each allowed to dry, then scraped and polished with a wet cloth or a smooth stone to a hard, dead-white surface with the texture of eggshell. A good gesso ground can take twelve or more layers and several days.

The drawing was then incised into the gesso with a stylus or drawn in dilute ink, and the areas to be gilded were marked out.

Gilding

Gold leaf was laid over bole, a fine red or yellow clay mixed with glue and applied over the gesso. The bole is what gives burnished Byzantine gold its warm tone; the red shows faintly through the leaf, which is around a ten-thousandth of a millimetre thick, and it also provides a surface soft enough to burnish.

The leaf was laid onto the bole wetted with dilute glue or size, then burnished with an agate or a dog’s tooth until it took a mirror finish. Gilding was done before painting, because burnishing is a vigorous operation, and because paint overlapping gold is acceptable while gold overlapping paint is not.

The meaning of the gold ground is discussed in the gold ground technique: in short, it is not a background but a space without location, standing for uncreated light.

The Paint

The binder is egg yolk, thinned with water and sometimes a little vinegar or wine to slow spoiling. Egg tempera dries in minutes, cannot be blended wet-in-wet like oil, and cures over months into a tough, insoluble film. It has to be built in many small, translucent strokes, which is precisely why icon painting looks the way it does — the hatched highlights on a face are a consequence of the medium as much as of style.

The pigments were those available in the medieval Mediterranean:

Colour	Pigment
Blue	Lapis lazuli (costly), azurite, indigo
Green	Terre verte, malachite
Red	Cinnabar/vermilion, red ochre, madder lake
Yellow	Yellow ochre, orpiment
White	Lead white
Black	Charcoal, lampblack, burnt bone
Flesh base	Ochres with green earth

Terre verte matters more than its dullness suggests: it is the standard base for flesh, and where the upper layers of an icon’s face have worn away, the surviving green underlayer gives old icons their characteristic olive cast.

Painting a Face

The sequence for a face is described in workshop manuals and confirmed by technical examination, and it runs from dark to light — the opposite of most western practice.

1. Proplasmos. A flat, dark olive-brown underpaint covering the whole flesh area.
2. Sankir / glykasmos. Successive warmer, lighter tones laid over the proplasmos in the raised areas — forehead, cheekbones, bridge of the nose — each smaller than the last, leaving the dark base visible in the hollows.
3. Highlights. Fine white or near-white lines (psimythia) on the brow, nose and cheekbones, applied last, drawn rather than blended.
4. Drawing lines. Dark outlines re-established around eyes, nostrils, mouth and the edge of the face.

The logic is that light is added to a body rather than falling on it from a source. There are no cast shadows in an icon because there is no lamp; the figure is illuminated from within, and the technique builds that up literally, layer by layer.

Garments follow the same dark-to-light progression, with folds indicated by lines of increasingly light tone rather than by shading, and gold striations (chrysographia) often laid over the drapery of Christ and the angels.

Varnish and Afterlife

The finished icon was left to cure and then varnished with olifa, a boiled linseed oil preparation. Olifa saturates the colours and protects the surface, and it also darkens steadily, going from pale amber to near-black over roughly eighty to a hundred and twenty years.

This has enormous consequences for how icons have been seen. A darkened icon was traditionally overpainted rather than cleaned, so that many old panels carry several complete later images on top of the original. The Russian rediscovery of early icon painting in the early twentieth century was literally a rediscovery: cleaning revealed that famous “sixteenth-century” icons were twelfth-century work under layers of later paint — the history of the Vladimir Mother of God is the best-known case.

The Manuals

No Byzantine painter’s handbook survives from the medieval period, which is frustrating, since we have Theophilus and Cennino Cennini for the west. What exists is later: the Hermeneia, the Painter’s Manual compiled by Dionysius of Fourna on Mount Athos in the early eighteenth century, which records recipes, proportions and iconographic prescriptions presented as ancient tradition.

The Hermeneia has to be used carefully — it is a post-Byzantine document describing an eighteenth-century Athonite workshop — but where it can be checked against technical analysis of medieval panels, the core of the method matches. Its prescriptions for the proportions of a figure (a head unit repeated nine times for the body), the mixing of flesh tones and the sequence of layers are consistent with what the panels themselves show.

Workshops and Signatures

Byzantine icons are rarely signed, and the reticence is deliberate: the painter was understood to be transmitting a received image rather than inventing one. Where signatures do appear they are often in the form of a prayer — “by the hand of” followed by a name — rather than an assertion of authorship.

This does not mean painters were anonymous drudges. Contracts, letters and monastic records name painters, record their pay, and show them travelling: Greek painters worked in Serbia, Russia, Venice and Crete, and the Cretan school of the fifteenth and sixteenth centuries ran a genuine export industry, producing icons to order in either the Byzantine or the Italian manner, sometimes specified in the contract.

Why the Method Persisted

Egg tempera on gessoed panel was replaced in western Europe by oil on canvas in the fifteenth and sixteenth centuries, and never was in the Orthodox world. Conservatism is part of the explanation, and so is the theology of the image, which puts a premium on faithfulness to received prototypes. But there is also a technical case: an icon made this way, kept out of direct sun and damp, lasts for a very long time. The Sinai panels discussed in the icons of Saint Catherine’s include sixth-century works in a condition that no fifteenth-century oil painting can match.

What Technical Analysis Has Shown

Scientific examination of icons has become routine since the 1990s, and it has settled several questions that connoisseurship alone could not.

X-radiography shows the panel’s construction — the boards, the dowels, the battens, old splits and repairs — and reveals lead white in the paint layers, which maps the highlights and often exposes an underlying composition different from the visible one.

Infrared reflectography penetrates the upper paint layers and shows the underdrawing: the incised or brushed lines the painter laid on the gesso. Comparing underdrawing to finished surface reveals how closely a painter followed a model and where he departed from it.

Cross-sections taken from damaged edges show the full stratigraphy — wood, glue, canvas, gesso, bole, gold, underpaint, modelling, glazes, varnish, and any later repaintings — and can be dated relatively.

Pigment analysis by X-ray fluorescence and Raman spectroscopy identifies materials, which constrains date and origin: Prussian blue means after 1704, and certain pigments indicate specific trade routes.

The results have repeatedly overturned attributions. Panels assumed to be late copies have proved to be early works under repainting, and celebrated icons have turned out to be composites of several campaigns. The most famous case is the Vladimir Mother of God, where only the faces are twelfth-century.

The Economics

An icon was an expensive object, and knowing roughly how expensive changes how one reads the survivals.

The costly components were gold leaf, lapis lazuli — imported from Afghanistan and, weight for weight, comparable to gold — and the painter’s time, which for a well-modelled face ran to days of work in many thin layers that each had to dry.

Contracts survive from the Cretan workshops of the fifteenth and sixteenth centuries and are unusually informative. They specify the subject, the size, the quality of the gold, whether the manner is to be alla greca or alla latina, the delivery date and the price. One well-known Venetian contract of 1499 commissions seven hundred icons of the Virgin from three Cretan workshops in forty-five days, in specified styles — evidence of an export industry working at something close to industrial scale.

At the other end, village churches were furnished with panels by local painters using ochres, earths and a minimum of gold, and these survive in quantity across Greece and Cyprus. They are technically the same object made cheaply, and they are the ones most Byzantines actually prayed in front of.

Later Repair and Its Ethics

Because an icon is a working religious object rather than a museum piece, the tradition’s own attitude to its material history differs from a conservator’s.

Historic practice was renewal: when varnish darkened or paint was lost, the image was repainted, often completely, sometimes several times across centuries. A metal revetment might be added, requiring nails through the panel. None of this was regarded as damage; the icon was being maintained in service.

Modern conservation, which strips later layers to expose the earliest, reverses that logic and has been resisted in some quarters for exactly that reason. Removing four centuries of accumulated devotion to recover a twelfth-century surface is a choice about what the object is for, and it is not a neutral one.

The compromise most institutions have reached is to clean where the later layers are failing anyway and to document everything removed. The arguments are live, and they surface whenever a famous icon goes into a laboratory.

• Byzantine Iconography — the conventions the technique serves
• The Gold Ground Technique — why the background is gold
• The Icons of Saint Catherine’s, Sinai — the oldest surviving panels
• Byzantine Frescoes — the same painters working on wet plaster
• The Theology of Icon Veneration — what an icon was held to be
• Byzantine Manuscripts — the same pigments on parchment
• The Vladimir Mother of God — an icon recovered from beneath its own repaintings