The image above is one I just found from the 1930's it was from a color transparency and it looks like the colors have shifted slightly. This image shows you how the marble was pieced together below the mosaic. This is the only picture I have found that shows the proportions of the figures. They are perfect and there is plenty of room for their feet and Christ's cushion if you remove one or both rows of marble. We know that the mosaic extended down to the bottom row because the mosaic setting bed was found behind the upper row, but not below it. The bottom row is intact because the wavy grain matches up.
Probes beneath the surface of the existing mosaic and cornice show that there was an earlier mosaic in the spot now occupied by the great Deesis. A number of gold tesserae made of darker glass were found beneath the cornice and these appear to be of sixth century manufacture.
The Deesis must have been completed in one summer season, from May - September, since there were two undercoats of plaster that had to dry before the final layer was applied on which the mosaic was set. The two under-layers were pretty straightforward. The first layer contained crushed brick, lime dust and chopped straw. The second layer was finer and upon this layer rough outline of the design of the mosaic was painted. The plaster on the Deesis panel was finely done with large trowels and has some variation in it on purpose. A slightly uneven surface would reflect gold mosaic in a lively, glittering way. When Justinian built the church in the sixth century the plaster work was fast and a bit sloppy - they had huge areas to cover - imagine the vast vaults to be done - in gold mosaic and not much time to get it finished. The uneven surfaces and joins of Justinian's time have given those mosaics a much admired, but unintended shimmer. It was much easier to lay plaster on a flat surface and fortunately, that's what our workmen had to cover here in the south gallery.
The same plastering method is found in Byzantine churches from Greece to Italy, Russia and Georgia. This technique remained the same for almost 800 years, until the end of the empire.
Before the mosaic artists began work, a huge number or mosaic tesserae had to be assembled in various colors according to hue and intensity of color. Each color might which require dozens of shades. Some mosaic was stone and other was glass. The stone tesserae included cubes of semi-precious stones, such as lapis lazuli and porphyry. However, it was the glass tesserae that had the strongest and most brilliant color combined with the subtle effects on light penetrating the cubes. A significant amount of the gold glass was from the 6th century and was 500 years old. The tones of gold ranged from deep yellow to a sun yellow and in many cases include what appears to be red gold and white gold. These variations are caused by the various colors of glass under which the gold leaf is laid, by the gold used, and sometimes by paint applied under the tesserae. In the background of the Deesis, silver is also found. Great care was taken with the selection of the gold. Our artists were experts at using various types of gold tesserae to create dazzling effects.
Byzantium was still one of the world-centers of glass production and its factories could produce tons of mosaic a year, which was exported throughout the empire, Western Europe and the Middle East.
Once the plaster had dried and set properly, work began on the topmost layer of lime and marble dust where the mosaic cubes would be set. This fine layer of plaster was applied in a patchwork of sections just large enough to be completed in one day's work. The plaster joins were easy for the restorers to see and record. It gave them a good understanding of how the mosaic was created. On this layer a detailed colored painting was prepared as a guide for the artists.
As a comparison to the Theotokos of Hagia Sophia, here is a close up of the Kress Madonna from the National Gallery of Art in Washington, D.C.. One can see the same almost excessive attention to graduated color and subtle shadow transitions in the Virgin's face. This is an example that typifies the essence of 'tenderness' icons which were popular in Byzantium in the mid-twelfth century and were exported across Western Europe and Russia. Works like this had a great influence on Italian artists like Duccio. Below it is a close-up of the famous Virgin of Vladimir, which was painted around the same time the Deesis was created.
Many Byzantine paintings and mosaics were done with stencils made from other works. This ensured that each icon was true to its prototype and could be trusted to be a true representation of the saint depicted. In some cases a talented and experienced artist could work directly on the plaster without preparatory drawings - but this was very rare and discouraged by some artists as reckless.
We don't know anything about the artists that created this mosaic. Were they monks from a monastery in Constantinople? Were they workers from an atelier in the city that was attached to or patronized by the Imperial court? Were they artists engaged by the patriarch brought in from provincial cities of a distant part of the Empire?
In the middle of the twelfth century, when our mosaic was created, Constantinople was a huge city of 400,000 people. The population had not been this big since the great plagues during the reign of Justinian reduced the inhabitants by almost two thirds in a few months. The growth in population was a reflection of the increasing wealth of the Byzantine Empire, and the growth in commerce between East and West that sailed into her ports and passed through the city's gates. Most of the daily trade and commercial activity, as in most mediaeval cities, was the day-to-day housing and feeding of the populace. However, one thing that set Constantinople apart from every other city in the empire were her luxury industries, like silk-weaving, gold working, glass, perfumes, fine books, furniture and works of art. Every Byzantine Christian household had at least one icon and most of them were inexpensive; one icon was equal to the cost of a good pan. Even the common people had an appreciation for art in Constantinople, since they were surrounded by the secular works of art from ancient Greece and Rome through the city's forums, squares and colonnaded streets. There were hundreds of churches and chapels crammed with the best Christian art to be found anywhere. We can't forget how filthy Constantinople was and the terrible juxtaposition of great wealth and poverty. This was one of things that struck people who visited Constantinople in this period. You could find fine nobles living in palaces--right next door to incredible squalor.
With so much to see in every quarter of the city, people took the art and monuments around them for granted (although they could be very superstitious about this statue or that column, giving them supernatural powers over the fate of the city), partly because it had been there all their lives and was a part of the day-to-day landscape, but then, the Byzantines always had a special relationship with art and beautiful things - especially when it was religious. New icons, mosaics and secular works of art were admired and noted by the public and talked about. Byzantine art glorified both the Imperial court and the church and the people of the city enjoyed it. A large educated class had the cultural backround to be savvy critics and patrons of art.
There was a mass market of icon painters that supported this class and iconography was subject to fads, changing tastes, and a growing sophistication in art across all classes. In the twelfth century, Constantinople must have boasted 10,000 icon painters competing for business. We can assume that there were very few freelancers and that most painters were part of a guild, attached to a specific religious community or working in established workshops. There must have been a staggering range of quality.
At the top of the artistic food chain stood the Imperial Court and the Patriarchal Church. Everyone wanted to work for them and be under their protection and sponsorship. This was not the only source of big commissions and major artistic projects. There were also fabulously wealthy nobles and rich monasteries who were proud patrons of art. I imagine in the twelfth century there was plenty of work and all of the important workshops in the city very busy with both religious and secular projects. Foreign commissions were also coming in for people such as the Norman Kings of Sicily. Like Florence in the fifteenth century, there were sophisticated buyers and workshops with reputation and experience to sell to them. Using Florence as an example we can see how an artistic explosion can occur where creative artists have wealthy patrons to support them.
In the twelfth century, Byzantium was at its medieval zenith of art and craftsmanship and there was enough business to keep workshops busy for several generations. This meant these ateliers - whether they were private or religious - had a unique opportunity to perfect technique and create beautiful things for an appreciative humanist audience.
The background of the panel is laid in a three-lobed motif and many of the gold tesserae are set at an angle. An amazing thing about our mosaic is the consistency and perfection of the gold background. The background is a masterpiece in its own right. No photograph can convey the effect of standing in front of this mosaic. Although the background would have been laid by workshop apprentices or assistants we can see how experienced they were in work that required great concentration and control. It was work that did not allow for mistake or later corrections. One only had a single chance to get it right before the plaster set.
It is a wonder to see the work that went into the halo of Christ. It has a subtle rinceau pattern that is only visible at certain times of the day when the light is just right. This is another example of how the mosaic was designed and executed just for this site-specific area in the church.
There is an obvious difference in the level of detail applied to the backgrounds and other parts of the mosaic. One can easily see a stepping up in the number of tesserae used per square inch from the garments to the hair, hands and faces. Indeed, the faces are laid in a painterly fashion with brushstroke-like lines ending in arrow-shaped slivers of glass and stone.
How much work could be done in a day? As mentioned above, examination of the setting bed clearly reveals the seams of each day's work. Along these edges cubes are more likely to drop away, leaving trails of missing tesserae where the patches of plaster adjoin one another.
Looking at the plaster, Whittemore and his team could tell the face, neck and beard of Christ were done in one session and the hair in a separate one. The clothing and throne would have gone faster, but there was a larger area to cover. Where one would have expected a simplification in the laying of the mosaic in the garments, this is only true to an extent. The clothing contains a myriad of colors and patterns that show the same level of bravura technique as the faces. Every inch of this mosaic shows a high degree of pride in workmanship. As mentioned earlier, many of the details would have been invisible to the viewer and only seen if you were right up next to the panel. So, if we suppose four to five men working on the panel at one time the entire work of laying the mosaic could be done in less than a month. I say four because I believe that is the maximum number that could work on the scaffolding at one time.
After the work was completed, it became a place of special worship and adoration. The marble floor shows the footprint of a low chancel-like enclosure and the marks of a large candle stand. If the mosaic pre-dated the Latin conquest of 1204 - as I believe it does - the mosaic must have made a huge impression on the Crusaders. Directly across from the mosaic, the notorious Venetian Doge, Enrico Dandalo had his tomb installed here in 1205, obviously to be close to this great work of art in the Great Church of the city his forces had just conquered.
In late Byzantine times the mosaic was carefully maintained and it shows places where minor repairs were made with cubes set in beeswax rather than plaster. As I have written in the history section, at some point the bottom of the mosaic became seriously damaged - I assert this must have been during the Latin occupation - and a row of marble panels was set along the bottom of the panel to conceal it sometime after the reconquest of the city by Emperor Michael VIII Paleologus in 1261. It seems to me there was no time to do a real restoration (even if they could have found the artists to do it) and there was obviously some urgent need to quickly spiff up this area of church and make it ready for some official use. Of course, we should keep in mind that the church was not an Imperial one, it belonged to the church and to the Patriarch - and it would have been the church authorities who had to tackle the huge job of making Hagia Sophia ready for religious use after the Latins had abused it for decades.