Russian Icons | Materials, Techniques, and Approaches to Conservation
The History of the Russian Icon
The roots of icon painting are as ancient as Christianity.  Derived from the Greek eikon, the icon is a religious image, typically executed on a wooden panel, consisting of various artist materials arranged in a precise sequence. The earliest icon in Christianity is considered the face of Christ, which was transferred by His face onto a cloth held by Veronica during the way of the Cross; in Russian, this image is referred to as “The Image Not Made with Hands” [1]. The importance of the icon developed during the earliest days of the Catholic Church, and was a fulcrum of dissention in the Iconoclasm that took place during the 8th-9th centuries (A.D.) The first historically and albeit, controversial documented artist to make icons was Luke the Evangelist in the 8th century (A.D.); his production of icons has been debated as a myth to validate the use of icons during this contentious period. During the 8th century A.D. and the second Ecumenical Council of Nicaea, the veneration of icons was supported, however, worship was not [2].  The artistic techniques of icon painting were developed in the 9th-10th centuries in the Byzantine Empire (Byzantium), during the Great Schism or break between the Roman Catholic and Easter Orthodox Church This is the pivotal time of spiritual revival in Byzantium and the genesis of the icon tradition as an important artform across Eastern Europe and missions throughout Africa and Asia. The Easter Orthodox Church formulated a doctrine that set up rules for veneration to ensure that they were not worshipped and provided technical guidelines for their production. The influence of icons in Russia appeared as a result of the missionary work of the Byzantine Church. With the adoption of Eastern Orthodoxy in 988 A.D., Russia integrated the Christian Eastern Orthodox culture in its already established form. In ancient Russia (9th-12th centuries), icon-painting played an important role; they were used for religious veneration and were typically unsigned. They were viewed as a sacred object rather than a work of art and were typically blessed by a priest prior to use. Russians present them in the Orthodox Sacraments and for protection. The composition and aesthetic presentation of icons was regulated by the Russian Orthodox Church during the mid 17th century. Practices introduced by Patriarch Nikon of Moscow resulted in a split in the Russian Orthodox Church; this deviated from the Byzantine tradition towards the realist and expressive compositions of Russian icons.  Icon making became one of the main forms of fine art in Russia; icon-painting centers and schools were opened and Russian artists developed their own aesthetic. The Russian iconographic culture was an organic synthesis of the Byzantine stylistic elements with a purely national style, deeply rooted in the highly developed pagan culture of the past age. Icons made in Russia, borrowing the traditions of the Byzantine icon, can be differentiated by its successors by the following characteristics:
• The religious inscription is Slavic, rather than Cryillic • The later Russian style of painting icons appears more emotional and expressionistic.  • Early Byzantine iconographers used different tones of colors to indicate shoulders, knees, and hips. Post ancient Russia, Russians
gave color a secondary role, being focused on the multiplicity of lines. • The Byzantine icon tradition utilized deep, bright colors; Russian iconographers usually use a restrained and subdued palette.
The subject of icon painting is broad and covers many types of traditions over a vast number of countries and cultures. This article will focus on the traditional materials and techniques used to create Russian icons, the condition issues that are presented due to age and deterioration, and the conservation efforts used by the Conservation Department of the Saint Petersburg Stieglitz State Academy of Art and Design to preserve them for future generations.

Russian Icons | Materials + Techniques
An icon (fig. 1) follows a traditional layer structure found on most tempera or oil paintings executed on panel. It has four or five layers arranged in the following order: the wooden support, the preparatory layer (chalk ground), the paint layer, and the protective varnish layer. The icon may, but not always have a fifth layer, called the riza (риза, "robe") or oklad (оклад, "covered"); the riza are embellishments made of metal or other decorative materials that adorn the painted image.
The Support
The first layer is the support and is most often a wooden board, prepared by a specialized craftsman instead of the artist’s workshop. Boards were typically made from lime (linde in Russian). Limewood was the most commonly used wood species due to its stability and resistance to warping and insect damage. In northern regions of Russia, a variety of conifers were used: pine, spruce, cedar, or larch wood. Depending on the desired size of the panel, the board may be made from a single piece of wood, or from two or more planks. The planks would be joined by mortise and tenon joints (shponki) or fastened with dovetail inserts (lastochki) (fig. 1). Occasionally, boards were adhered with sturgeon glue, and after the late 15th century, with casein glue. Tool marks from an ax or saw from when the planks were made, are often visible in raking light on the reverse of the panel.
FIGURE 1A . Front of a Russian Icon. "Holy Image of the Saviour Not Made by Hands" , early 19th century, Trinity Church in Arefino (Aferinskaya Troitskaya tserkov), Nizhny Novgorod, Russia
FIGURE 1B . The verso of the icon. 
The board may or may not be covered with resin as a protective layer against fluctuations in relative humidity and temperature. After the panel was made, the front surface would be scored (scratched into) to provide tooth for the application of the preparatory layer.
The size of the icon depends on whether it is an intimate object for private devotion, or for public veneration at a Church. Personal icons may measure from 2-19 inches in height; one of the most frequently observed size is called a “hand-sized” icon. In addition to the personal “hand-sized” icon, families would commission larger panels for a wedding or birth celebration. A wedding icon traditionally depicts an image of the Savior or Mother of God. An icon commissioned for a birth of child would depict the newborn’s patron saint; the board would be sized to the height of the baby, but typically would be no more than 19 inches. The sizes for icons commissioned by the Church would vary depending on the size of the Church and the height at which the icon was hung; however, the most common size is similar to a book and measures 11 x 15 inches.  An Easter Orthodox Church typically has an
: a wall of paintings and icons to separate the sanctuary from the nave. Traditionally, the iconostasis is very large, beholding images that may reach 98 inches in height. The iconostasis is divided into five sections or rows; the size of the icons in the iconostasis relate to its placement in these five rows. The five rows from the bottom to the top are: Sovereign or Growth, Festive, Deisis, Forefathers, Prophetic. The Growth icons would be no less than 39 inches so that the image could be seen from the front of the altar.
The Prepatory Layer
Prior to the application of the chalk ground, usually a linen cloth (pavoloka), was pasted on to the panel with animal hide glue to provide additional tooth for the ground layer.  Sometimes the panel does not have a cloth layer and the ground is applied directly to the panel; however, it is rare that the support of a tempera work was prepared with only cloth.. On top of the cloth, the second layer, which is called a ground or preparatory layer, is applied. The ground was typically made from either chalk or gypsum mixed with glue. It decreases the absorbency of the panel so that the paint layer can be applied without sinking into the support. Several layers would be applied and intermittently sanded down to create a smooth surface for the application of paint. Typically, the ground layer is ivory in color due to the natural coloring of both chalk and gypsum. After the 15th century and invention of oil paints, colored grounds came into use to alter the optical effects of using pigmented glazes. In this case, the chalk or gypsum based preparatory layer would be mixed with earth pigments to give a warm or cold hue to the resulting color palette. During this time tempera may also be combined with pigments ground in different binders (i.e. Gum Arabic, oil, and less so animal hyde glue).
The composition would be mapped out with an underdrawing, made with either charcoal or an ochre-colored wash. The underdrawing would be applied on top of the ground, serving as a guide for both the application of tempera and gilding. The central lines of the drawing were sometimes scratched with a sharp needle, for the purpose of preserving the preliminary drawing after applying red bole or tempera. Often, the composition would be copied and traced from another image. The practice of tracing in Russia was associated with the Stoglav Synod of 1551. This council specifically warned icon painters against designing their own compositions and urged them to use compositions of ecclesiastically sanctioned icons. Artists used paper tracings or books containing a collection of patterns intended as guides for icon painters. 
Gold leaf was mainly used for gilding the backgrounds of the icons. An additional preparatory layer, “the bole”, would be applied on top of the ground in areas where gold leaf would be prepared. This layer has a red-orange appearance typically made with ochre pigments; however, red lead and in more modern periods, Armenian bolus, have also been used. The gold leaf used in early Russia was denser than that of the Russian icons made after the 15th century; up until this period, the gold used had a high silver concentration as a component. This resulted in a visibly green oxidation product, projecting a greenish-hue not typically associated with gold. Gold appearing bright yellow or reddish in color typically has a small mixture of copper.
For many centuries Russian icons were painted with tempera, since it was the central binding medium used across Europe until the wide spread use of oil; the term used today is "egg tempera", or simply "tempera". This medium uses egg yolk as the binder for pigments.  The paint layer consists of finite brush strokes of pigmented medium applied successively to the ground layer. The optical effect of glazing achieved with oil paint is not possible with egg tempera due to the opacity of the medium. Under the influence of Western European art and the “invention of oil” in the 17th century, oil could mixed with tempera or used on its own for the creation of icons. During this period, the so-called “Fryazhskaya manner" of painting developed, which not only combined the stylistic features of old Russian and Western European art, but also the two techniques of tempera and oil painting.
The Varnish Layer
The fourth layer is a protective and saturating layer of linseed oil varnish or other natural oil-based varnishes (olifa); sunflower, and poppy seed oil was also used [3].  These oils produced a warm, pleasant glow and also protected the paints from deterioration associated with the devotional practices of the faithful such as votive candles or incense. Occasionally in aged oil, strongly heated (250-325 °C, 482-617°F) amber was dissolved to obtain amber drying oil; this creates a particularly hard film that is often hard to soften in solvents. On rare occasions, egg white was used as a material for the protective layer; this occurs mostly on Belarusian and Ukrainian icons.
The Riza Layer
The fifth layer, which is not always used, is the riza layer. Rizas or oklads were applied as early as the 11th and 12th centuries[4].  Rizas can be made of metal, embroidered fabric, and even carved wood covered with gesso and gilding. Rizas were not applied to the entire painted surface but were used for decorative details, specifically halos; an oklad, more specifically would cover the entire icon except for the face and hands. These decorative pieces were fabricated separately and affixed to the finished icon with nails. Brass and silver nails would result in unwanted oxidation products that aged unsympathetically to the silver. In the 17th century, a type of Riza called the basma (басма), was the most prominent decorative addition; it consisted of a handstamped sheet of silver and attached to the icon with silver nails [5]. After the 17th century, rizas were more often made of gold, gold-plated silver, silver, brass, copper, or other similar alloys [6]. Depending on the importance of an icon, these decorative elements may include the addition of enamels, and precious stones. All of these decorative elements were to impress upon the viewer the sacredness of the object that they beheld. During the 19th-20th centuries, these elements provided a façade to unpainted parts of the icon.
Case Study | The Conservation of Russian Icons
In the summer and autumn of 2012, the Commission for the Preservation of Russian Monuments conducted an expedition along the upper and middle reaches of the Volga and Oka rivers. The Commission consisted of professors and students from the Conservation Department of the
Saint Petersburg Stieglitz State Academy of Art and Design
.  In the autumn and winter of 2012, the expedition participants assessed a few Russian icons for treatment. The icons assessed date to the early 19th century. Most of the icons were in poor condition: the spiritual traditions related to the veneration of the Russian icon were lost during the entirety of the 20th century; during this time, the icons were not properly cared for. The next part of this article presents a case study that highlights the conservation techniques and analytical research used for the preservation of the "Holy Image of the Saviour Not Made by Hands"; this early 19th century icon hangs in the Trinity Church in Arefino (Aferinskaya Troitskaya tserkov), Nizhny Novgorod, Russia (fig.1a). The Trinity Church in Arefino was built in 1643 and has held several uses over the centuries that contributed to the icons condition in the 20th century: On November 22, 1938, the church was closed and given over to a club for factory personnel; In 1946, a galvanizing plant was placed in the building; In January 2008, the Church was returned to the Nizhny Novgorod diocese.

This icon was held on the icon stand, called “analogion” or “analoi” stand. This is a narrow, chest-high wooden table on which smaller icons of Saviour and the Mother of God, are traditionally placed for a feast day or celebration; the stand is located immediately before the Iconostas.
FIGURE 1A. "Holy Image of the Saviour Not Made by Hands" , early 19th century, Trinity Church in Arefino (Aferinskaya Troitskaya tserkov), Nizhny Novgorod, Russia
FIGURE 2A. Trinity Church in Arefino (Aferinskaya Troitskaya tserkov), Nizhny Novgorod, Russia
FIGURE 2B. Trinity Church in Arefino (Aferinskaya Troitskaya tserkov), Nizhny Novgorod, Russia
Case Study | The Condition
The entire surface of the icon was considered to be in fair condition and required immediate intervention.  The boiled linseed oil varnish had severely darkened with time, appearing dark brown in color; the severity and distribution of the original olifa layer created an uneven opaque film that obscured the image. The varnish had been selectively cleaned in the past by a non-specialist; the original linseed oil varnish was missing on the face of the Savior, the faces of the right and left angels of the Lord, and abraded glazes. Selective cleaning has occurred often over the past three centuries where both the varnish and grime on the central part of the composition is cleaned, but the remaining parts are not. This could be due to pigment sensitivities in a time of limited conservation research or the historical aesthetic need to remove yellowed surface coatings from flesh tones. In this case, there is disharmony to the color palette used to depict the composition. The icon consists of four boards joined by two flush parallel dowels driven through the center of each panel.  The boards and dowels are made of the same coniferous wood, presumably limewood. There are numerous scratches on the surface in alternate directions. There are losses of wood and exit holes on the surface caused by insect damage; these are located mainly around the perimeter of the icon and the reverse near the joins. At the time of examination, there were no active wood worms; therefore, the panel did not need to be treated for insect infestation. The front side of the icon panel has a cut-back center portion.  The ivory-colored ground is chalk-based. This dense layer of ground has been thinly applied over the entire surface and has yellowed with age. There were localized areas of flaking and raised paint accompanied by several losses of ground, specifically along the edges of the icon. The paint layer was executed in thin brush strokes of tempera. There are correspondent losses of paint to the loss of ground. There was a fine, horizontal, craquelure pattern observed across the entire surface of the icon.
Case Study | Technical Analysis
Prior to treatment, technical analysis was conducted to examine the composition of the organic component of the varnish and the stratigraphy of the paint film. All tests were performed in the laboratory of the State Russian Museum. The following research methods were used for the analysis: a) Reflected nonpolarized light microscopy (magnification of 10x to 100x) b) Polarized light microscopy ("BIOLAM", magnification of up to 600). c) Histochemistry. This is an analytical method for determining the type of binder material and assessing its spatial distribution (spreading) with microscopy and microstaining tests. d) Thin-layer chromatography to identify organic dyes
FIGURE 3 . A sample used to identify the the organic component in the cover layer.
FIGURE 4. A sample used to identify the the organic component in the paintlayer.
As a result of microchemical studies it was discovered that the oil varnish is based on a solid natural resin, such as amber or copal. Additional testing with FTIR to identify the organic compound was not carried out. Additionally, the microchemical studies of the ground and paint layer, revealed the following stratigraphy:
A sample of dark maroon on a cream-colored ivory ground (fig. 3) 7. A layer of contamination — dirt and grime. 6. A layer of oil varnish. 5. The top, most visible layer of paint: a layer of crimson-red overpaint, which was identified as an organic lake pigment on a wax-resin binder. Both alizarin and purpurin were identified using polarized light microscopy (PLM). 4. A layer of oil varnish. 3. A layer of red pigment that was determined to be ochre tempera using PLM (fig. 4). 2. A layer of tin. Tin was used for the gilt background, and is often found on icons of the 19th century. It is a cheap substitute for gold or silver. 1. The ivory ground of talc with gelatin glue as a binder; identified with histochemistry.

Case Study | Treatment
The darkened oil varnish needed to be sufficiently reduced or removed so that the icon would be legible; this would be difficult due to the hardened and cross-linked nature of the aged linseed oil varnish. Testing was carried out on a small area above the angel’s right wing to determine the best method to safely reduce the varnish layer. Both mechanical action using a microscalpel and solvent tests were trialed. It was not possible to thin the varnish layer by layer using a microscalpel without risking damage to the paint layer. Microemulsions were tested and applied with a cotton swab; they were tested in combination with the microscalpel. The results of these tests are as follows: • pinene removes non-persistent surface grime • 1:3 isopropanol with alpha-pinene — flax-seed oil varnish moved slightly,
but it softens unevenly
• 1:2 isopropanol with alpha-pinene 1:2 — flax-seed oil varnish softens
unevenly. • 1:1isopropanol with alpha-pinene 1:1 — flax-seed oil varnish softens
unevenly, and the use of the substance results in excessive drying or
blanching of the surface. • The use of ox-gall on a cotton swab resulted in varnish swelling and its
uniform softening, but it was not sufficient. • Ox-gall in combination with a Petenkoffer box [7], with an exposure of
several seconds to two minutes, was sufficient to swell and remove the
varnish evenly. The exposure time depended on the hardness and
thickness of the varnish in different areas (fig.5). Ox-gall residues were
removed with pinene.
FIGURE 5. The process of removing varnish
The gradual uncovering of the paint layer was carried out according to this well-developed method: the layers of varnish were removed or reduced with a step-by-step thinning process, utilizing the ox-gall/Petenkoffer box combination. There were four layers of varnish present in the initial testing area, as opposed to the two identified in analysis; the sample taken for analysis was in an area of selective cleaning that contained less varnish. The four layers of varnish were as follows: 1st layer: the top coat of varnish, non-original 2nd layer: a strip of varnish thinned to half of its initial thickness, non-original 3rd layer: the underlying layer of artist-applied varnish with black dot-like inclusions (presumably soot) 4th layer: a thinned layer of varnish applied to the tempera paint film by the artist
The removal was continued down and to the left. Most of the angel’s wing depicted on the right was revealed. The contours of the wing are made in black paint, with hatched brushstrokes modeling the feathers of the wing. During the thinning process, the area being exposed was rubbed with pinene to improve the optical perception of the exposed surface.
The cleaning of the area under the right hand of the right Angel of the Lord was difficult due to the very rough varnish coating, which was uneven and had protruding black bumps (figs. 11-12). The black bumps are related to the oil drying process in the “olifa” layer; the phenomenon may occur if the oil is applied too thickly or too much siccative is added to the mixture. There was risk of solubilizing the darkened varnish into the deep cracks and uneven cleaning.
FIGURE 11. During varnish removal. The cleaned area is on the right.
FIGURE 12. Area of very rough, uneven, with protruding black bumps varnish coating layer.
It was decided to thin the uneven varnish in the following way: The bumps were mechanically ground off with a boring tool (a wooden stick with a fine emery paper fixed at the end), in a circular motion; the resulting varnish dust was removed with pinene. When the surface of the varnish was even, the thinning of the varnish proceeded according to the previously developed method described above. (figs. 13-14).
FIGURE 13. Figure 12 during varnish removal.
FIGURE 14. Figure 12 after thinning the varnish and removing the oil protrusions.
In the process of thinning the varnish, a bright red himation with gold hatching and a dark green chiton with gold hatching were revealed. The paint layer was worn through to the dark ground in places, and the neck was painted in light ochre with white paint strokes. The hair was painted with white paint, utilizing individual brushstrokes to build a series of strands forming voluminous curls. This area was also severely worn, with local exposure of the tin and framed with dark and semi-transparent umber-colored sections. The halo of the angel is made with a red outline.  The varnish on this exposed area was also very rough, uneven, and contained protruding black bumps. Thinning of the varnish was done according to the method described above (figs.15-18).
FIGURE 16. During varnish removal
FIGURE 15. Before Varnish Removal
FIGURE 17. After varnish removal
FIGURE 18. During treatment: varnish removal.
In the process of treating the right part of the icon, the entire upper field and on the left side of Jesus Christ’s face, the paint layer started to delaminate due to poor adhesion between the paint film and tin layer.  A 3% (w/v) aqueous solution of gelatin glue (mezdrovy) was applied to these areas and covered with acid free tissue paper; afterwards, it was dried with a warm cast iron (~ 50°C) through filter paper.  After drying, the areas were additionally smoothed with a fluoroplastic spatula. The tissue paper was removed with a wet cotton swab. The result of reinforcement was positive, as all the flaking areas were successfully consolidated. Once the layers of darkened varnish were successfully reduced, losses and abrasion of original paint and ground were reintegrated using filling and retouching. Inpainting was performed utilizing the Pointillé technique with watercolors in a tone close to the surrounding original paint film. After inpainting was complete, a protective coating of 1:3 dammar varnish:pinene was applied to the surface.
Espinola, Vera Beaver-Bricken. "Russian Icons: Spiritual and Material Aspects." Journal of the American Institute for Conservation 31, no. 1 (1992): 17-22. Accessed October 20, 2020. doi:10.2307/3179608.

[2] Wikipedia, "Second Council of Nicaea". Accessed 9/6/2020.

Espinola, Vera Beaver-Bricken. "Russian Icons: Spiritual and Material Aspects." Journal of the American Institute for Conservation 31, no. 1 (1992): 17-22. Accessed October 20, 2020. doi:10.2307/3179608.
[4] Espinola, Vera Beaver-Bricken. "Russian Icons: Spiritual and Material Aspects." Journal of the American Institute for Conservation 31, no. 1 (1992): 17-22. Accessed October 20, 2020. doi:10.2307/3179608.
[5] Espinola, Vera Beaver-Bricken. "Russian Icons: Spiritual and Material Aspects." Journal of the American Institute for Conservation 31, no. 1 (1992): 17-22. Accessed October 20, 2020. doi:10.2307/3179608.

[6] Espinola, Vera Beaver-Bricken. "Russian Icons: Spiritual and Material Aspects." Journal of the American Institute for Conservation 31, no. 1 (1992): 17-22. Accessed October 20, 2020. doi:10.2307/3179608.
[7] A Pettenkofer box is used to perform regeneration of the varnish layer. Usually, it’s a plywood rectangle box with wooden sides. The height of the sides is about 1”-1 ½ “inches. Inside there is a layer of flannel, drape, or other thick material that absorbs alcohol well. The Pettenkofer method is used to regenerate varnish films from the surface by shallow decomposition. In this case, this method was used to “soften” the varnish layer followed by using Ox-gall.