Glossary |
a b c d e f g h i j k l m n o p r s t u v w |
Abbey, Edwin Austin
(1852–1911) An American illustrator and muralist. Abbey was a friend
of Sargent’s, and the two shared a studio in England where they each
created murals for the Boston Public Library.
archangel
A chief angel. The archangels are most commonly identified as Michael, Raphael, Gabriel, and Uriel.
Acryloid® B-72
A registered trademark (Rohm & Haas) for a very stable, clear acrylic resin used in conservation as a coating, a consolidant and an adhesive. It is composed of ethyl methacrylate and methyl acrylate copolymers.
armature
A framework used by a sculptor to support a form made of a malleable material.
Astarte
Also known as Ishtar or Ashtoreth. Ancient Near Eastern goddess associated with fertility and war.
atelier
The studio or workshop of an artist that is also set up as a place to train students in the basic principles of the practice of art.
auto-fluorescence
The property of certain materials to fluoresce when exposed to ultraviolet light.
batten
A narrow strip of wood used for structural support, for example, on the back of a panel painting.
to alphabet Beaux-Arts
A fine arts style developed at the Académie des Beaux-Arts in Paris
during the 19th century. The style draws on classical and
Renaissance sources for inspiration.
bezel
An encompassing rim, usually of metal, that surrounds and holds a
jewel, stone, etc. This rim is often affixed to a flat piece of
metal, forming the lip of a cavity that holds an object in place.
binder
See medium.
blind cleavage
A condition describing paint that has begun to detach from its
support layer but has not cracked or formed a ridge. Often caused by
moisture infiltration, blind cleavage is not as noticeable as tenting
and can be difficult to repair.
buffer
A chemical that allows control of the pH in a water-based solution.
to alphabet Byzantine
The style associated with the Byzantine Empire (330–1453 c.e.), characterized by a preference for hieratic, icon-like figures in front of a gilded background.
canvas
Fabric, most commonly linen or cotton, used as a support for painting.
carbohydrate
Any compound that contains sugar as a structural unit. Carbohydrates include monosaccharides (fructose, glucose), disaccharides (sucrose, maltose, lactose) and polysaccharides (starch, cellulose, gum, agar, carrageenan). Carbohydrates can be used as paint binders, varnishes, adhesives, and sizing agents.
Carolus-Duran (Charles-Emile-Auguste Durand)
(1837–1913) French painter, best known for his fashionable portraits. Sargent studied with him from 1874 to 1875.
cartoon
A full-size preparatory drawing made as a pattern for a painting, fresco, textile, etc. The drawing is transferred to the final support through tracing or pricking the outlines.
to alphabet cartouche
Architectural ornament in the form of a scroll.
casting
A sculpture process by which an original clay or wax model or
ornament can be reproduced. A liquid such as plaster, metal, or compo is poured into a mold and allowed to harden, creating a cast. Three types of molds are common: waste molds, piece molds, and gelatin molds. Waste molds are chipped away (wasted) to reveal the hardened cast, while gelatin and piece molds can be carefully removed and
re-used.
chelator
A chemical compound often added to cleaning solutions to attract and hold metal ions present in grime or soil. Triammonium citrate and ethylenediaminetetraacetic acid (EDTA) are examples of chelators used in art conservation.
cherubim
The second of nine orders of angels. They are usually depicted as heads with multiple wings.
to alphabet Christian trinity
One god existing in three persons: Father, Son, and Holy Spirit.
cleaning window
In art conservation, an area of a painting or surface that conservators have cleaned in order to give a preview of the final appearance of the entire object being treated.
clearance
The removal of residues from a surface, using water and solvent rinses.
Joseph Colletti
(1898–1973) An American sculptor who executed portraits, religious works and memorials. He assisted John Singer Sargent with the plaster relief work in the ceiling of Sargent Hall at the Boston Public Library.
compo
Also called “composition plaster.” A general term for various plaster mixtures devised in late-18th-century England. It is often composed of chalk, resin, and animal glue, and is used chiefly for ornamentation. Because this material hardens rapidly and is crack resistant, casts made from it could be coated or painted soon after drying.
to alphabet Constantine
(ca. 280–337 c.e.) The first Christian emperor of Rome and founder of Constantinople (now Istanbul). According to legend, before an important battle Constantine dreamed that a cross appeared in the sky, and he heard a voice declaring “In hoc signo vinces” (By this sign shalt thou conquer). The emperor and his troops subsequently vanquished the enemy, and in recognition he replaced the Roman emblem of the eagle on the imperial standards with the sign of the cross.
cope
A hooded ecclesiastical vestment (cloak).
Covenant
The promise or bond between God and the Israelites, central to the Hebrew scriptures.
cross-section
A small paint sample that usually consists of multiple paint layers. Conservators study these samples under the microscope to determine the layered structure of the paint film; they also use the samples to identify pigments.
Delivery Room
Now referred to as the Abbey Room, it is located on the Blagden Street side of the Library building. Formerly called Delivery Room because for many years books were delivered to readers there from the stacks, via a book railway.
to alphabet detergent
A material used to remove grime or dirt from a surface or substrate.
dogma
Dogma is the term applied to those doctrines held by the church, especially Roman Catholicism, to be normative for its members. These beliefs are understood by religious authorities to be so fundamental that to deny them constitutes grounds for excommunication or expulsion. Dogma is thus a narrower and more fixed term than doctrine or teachings; many doctrines do not have dogmatic status.
drying oil
Plant-based oil that forms a hard film by absorbing oxygen from the air. Examples of drying oils used as binders for paint include linseed (from flax plants), walnut, and poppy oils.
electromagnetic spectrum
The full range of radiation, organized by wavelength and measured in nanometers, that characterizes light. Forms of electromagnetic radiation range from ultra short gamma rays to very long radio waves. Only a narrow band of the electromagnetic spectrum, visible light, is detectable by the human eye (from about 380 to 750 nanometers). Forms of electromagnetic radiation invisible to the human eye that conservators use to examine paintings are infrared light, ultraviolet light, and x-rays. Infrared radiation has a slightly longer and ultraviolet a slightly shorter wavelength than the visible region on the spectrum. X-rays have a much shorter wavelength than visible light.
electrostatic forces
Forces of attraction and repulsion that occur between charged particles. Oppositely-charged particles attract; like-charged particles repell.
to alphabet emboss
To decorate with a raised pattern or concave design. The designs are stamped onto paper, leather, metal, and other materials with various tools.
Enlightenment
18th-century philosophical and sociological movement that insisted on the rights of the individual and the primacy of reason over existing customs and religious practices.
epoxy
A thermosetting polymer composed of two parts that, when mixed, form a hard solid. Epoxies are typically dense, stable materials often used as adhesives or coatings.
eucharist
The Christian sacrament of holy communion, in which the participants ritually consume the sacrificial body and blood of Christ in the form of the wafer (host) and wine.
Evangelists
The presumed authors of the Christian gospels: Matthew, Mark, Luke, and John. They are sometimes represented by their symbols: a man (Matthew), a lion (Mark), an ox (Luke), and an eagle (John).
fill
A substance placed in an area where the original paint has been lost to level the area before inpainting. Fills can be composed of various materials, including gesso (a mixture of animal glue and calcium sulfate) or chalk mixed with various binders.
to alphabet Frazer, James
(1854–1941) Scottish scholar and anthropologist, best known for his book The Golden Bough, 1890–1915, a groundbreaking multivolume study of comparative religion and mythology.
fresco
Also called true fresco, buon fresco, wet fresco. Method of painting on freshly applied, damp lime plaster with pigments ground in water (without the addition of a medium). As water evaporates from the plaster, the pigments adhere to the wall and are incorporated into a limestone crust.
fresco secco
Technique of painting directly on a dry plaster wall with pigments ground in a medium (such as glue or egg yolk). “Secco,” which means “dry” in Italian, refers to the condition of the wall when the paint is applied.
frieze
A horizontal band of decoration, sculpture, or painting, usually in an architectural setting.
Fourier transform-infrared (FT-IR) spectroscopy
An instrumental technique used to determine the identity of a wide variety of materials, including pigments and binding media. Infrared light is absorbed by the chemical bonds, causing them to vibrate, stretch and rotate. These movements are measured in wave numbers to give an infrared spectrum of absorbance and transmittance. The distribution of the peaks is particular to the chemical bonds under scrutiny, leading to the identification of the compounds in the sample. FT-IR spectroscopy requires a sample from the object, but the sample can often be used again for other analyses.
gilding
A thin gold layer covering a surface. While there are numerous gilding techniques, Sargent gilded his mural and relief surfaces in Triumph of Religion by adhering thin sheets (“leaves” or “foils”) of gold, or by applying gold paint.
to alphabet glazing
Glass set in a frame or sill.
ground layer
A paint primer applied to a canvas, which provides a relatively smooth surface to paint on and also serves as a sealant for the porous canvas.
halftone
A photomechanical process in which the original image is re-photographed through a screen that breaks up the image into a series of dots of various sizes, depending on the varying dark and light areas of the original. The new image is then transferred to a printing plate so that multiple copies can be made. The halftone process was invented in the 1880s, and it revolutionized reproductive photography.
Horus
Ancient Egyptian deity, son of Osiris and Isis. Usually depicted in the form of a falcon or falcon-headed man.
iconography
The study of the subject matter of works of art, and the subject matter’s possible meaning.
to alphabet impasto
Thick application of paint using brushwork or other methods; this buildup is readily visible to the naked eye.
Inframetrics
The InfraCam infrared camera, made by Inframetrics (now made by Swir), is equipped with a platinum silicide (PtSi) charged couple detector (CCD) that converts radiation incident on the detector surface into an electronic image. This camera is sensitive in the infrared band of the electromagnetic spectrum (1.1–1.5 microns). It produces a low-resolution digital image (256 x 256 pixels). IR cameras are used in conservation to detect underdrawings and compositional changes below the paint surface of works of art.
infrared (IR) light
Invisible radiation that can be used to detect underdrawings and compositional changes beneath the paint surface. IR wavelengths are longer than those in the visible range of the electromagnetic spectrum. In the IR examination of paintings, radiation from the near-infrared region (about 750–2,500 nanometers) is used.
infrared photography (IRP)
Photography that registers infrared light. This requires special film and lens filter, but can be done with a normal camera. IR films are sensitive to around 900 nanometers, or just beyond the visible range in the electromagnetic spectrum. Digital cameras, some of which are more sensitive than IR film, can also be used for this purpose.
infrared reflectography (IRR)
A method developed to overcome the limitations of infrared
photography (IRP) in revealing underdrawing by penetrating further
into the infrared part of the spectrum. Recent digital cameras are
equipped with infrared detectors that are sensitive up to 1,500–2,500
nanometers; filters can be used to further regulate the wavelength of
study.
to alphabet inpainting
Painting executed by a conservator to reduce the visibility of a damaged area in the paint film. Conservators restrict their use of this technique to the area of loss.
Isis
Ancient Egyptian goddess of the moon; wife and sister of Osiris, and mother of Horus.
James, William
(1842–1910) American philosopher and psychologist; brother of author Henry James, and author of The Principles of Psychology, 1890, and Varieties of Religious Experience, 1902.
Jehovah
Judeo-Christian name for the god of the Israelites, derived from Yahweh.
kore
A free-standing sculpture of a girl or woman in the Archaic Greek style (ca. 8th–6th century b.c.e.).
to alphabet lime
A traditional component of plaster used since antiquity. Lime (calcium oxide) is prepared for plaster by heating limestone (calcinated calcium carbonate) and then slaking (immersing) it in water to form calcium hydroxide.
Lincrusta-Walton
An embossed, pressed wall covering composed of drying vegetable oils, wood flour, filler, and pigment. Its manufacture began in the 19th century in England, when it was widely used as a textured wall covering. It was produced in Sunbury, Surrey, about twelve miles from Sargent’s Fulham Road studio. Sargent chose a corrugated version of it for decorative borders and certain images in Triumph of Religion.
loggia
A covered gallery or room that is open on one or more sides. Columns or a colonnade often separate the room or gallery’s open sides from adjacent spaces.
louver
A movable slat that can be opened and closed to control levels of light.
lunette
In architecture, a semicircular-shaped space, especially a wall bordered within the curves of an arched roof.
to alphabet marouflage
A technique for adhering canvas paintings to walls that evolved as early as the 17th century in France. Early recipes for this technique included pitch, wax, resin, and red ochre. In the 19th century, bone glue (a strong carpenter’s glue made from animal parts) or oils and varnishes were combined with lead white, which promotes fast drying. The adhesive used for the Sargent murals at the Boston Public Library contains lead white pigment in oil.
matte
Non-reflective. Describes the quality of a surface that is not glossy.
McKim, Mead and White
Charles Follen McKim (1847–1909), William Rutherford Mead (1846–1928), and Stanford White (1853–1906), partners in the architectural firm responsible for the Boston Public Library; they were arguably the most influential trio of architects in late-19th-century America.
medallion
A disk-shaped decoration. Sargent’s were cast in plaster or papier-mâché and gilded. The word “medallion” is used to differentiate Sargent’s large round reliefs from his reliefs in other shapes.
medievalizing
An artist’s attempt to render an image in a deliberately archaic manner based on contemporary notions of the style of the Middle Ages.
to alphabet medium
Also called binder, binding agent, vehicle. A liquid material in a paint mixture in which pigment particles are suspended and bound, such as oil, glue or egg yolk, or synthetic polymers. The medium must dry to a solid, binding the pigment particles into a film that is secured to the substrate such as canvas.
medium format camera
Medium format is a high quality camera, which typically uses 120 or 220 roll film. Modern medium format cameras often have interchangeable film cassettes, which in this case is substituted for a high resolution digital back manufactured by PhaseOne.
menorah
In its original Hebrew, this term might mean any lampstand. In Hebrew scriptures it refers to the seven-branched lampstand (or “candlestick,” as Sargent called it) of the temple and tabernacle as well as to the lampstand in Zechariah’s vision (Zechariah 4:2 and 4:11). Many are familiar today with the nine-branched menorah used in observances of Hanukkah.
messianic era
The Jewish prophecy concerning the coming of one through whom death and famine will cease, good will triumph, and all will live in harmony. Christians interpret Jewish messianic prophecies to refer to Jesus.
mineral spirits
A chemical derived from petroleum that is used as a paint or varnish thinner. It is used in conservation to dissolve oily or waxy materials on works of art.
model
A preliminary study or plan for a work of art, typically made on a smaller scale than the final version.
molding
A decorative, raised band used on architectural surfaces.
to alphabet Moloch
Ancient Middle Eastern deity to whom followers offered human sacrifices. Often referred to in the Hebrew scriptures as Baal.
monotheism
Belief in one god.
monstrance
A receptacle to hold the eucharistic host (consecrated wafer), usually constructed with a glass window so that the wafer within can be seen.
Mount Sinai
Sacred mountain where Moses received the Ten Commandments engraved on two stone tablets.
Mysteries of the Rosary
In Roman Catholic theology the term mystery signifies certain major events in the lives of Jesus and the Virgin Mary. The fifteen Mysteries of the Rosary divide into three sets of five: the Joyful Mysteries, the Sorrowful Mysteries, and the Glorious Mysteries. The Joyful Mysteries are the Annunciation, the Visitation, the Nativity of Christ, the Presentation of Christ in the Temple, and the Finding of the Child Jesus in the Temple. The Sorrowful Mysteries are the Agony in the Garden of Gethsemane, the Scourging of Christ, the Crowning with Thorns, the Carrying of the Cross, and the Crucifixion. The Glorious Mysteries are the Resurrection, the Ascension of Christ, the Descent of the Holy Spirit at Pentecost, the Assumption of the Virgin, and the Coronation of the Virgin. Contemplation of the mysteries figures in the devotional exercise of praying the rosary, their number corresponding to the fifteen sections in which the beads are strung.
to alphabet niche
An architectural recess or cavity in a wall.
Neith
Ancient Egyptian sky goddess associated with creation myths and with the cyclical passage of day to night to day.
Osiris
Ancient Egyptian god of fertility and god of the underworld. Husband and brother of Isis and father of Horus.
paint
A mixture of pigments and medium that dries to form a hard film.
paint sample
A tiny flake of the paint surface removed for pigment and/or medium analyses.
to alphabet papier-mâché
A mixture of paper fibers and binding agent, layered over a form. The mixture hardens and takes the shape of the underlying form. Binders include various pastes (wheat flour, rice flour, isinglass, gelatin) and resins.
Passion of Christ
The events before and after the Crucifixion of Christ, including the Last Supper, the Agony in the Garden, the Betrayal of Peter, Christ before Pilate, the Mocking of Christ, the Road to Calvary, the Crucifixion, the Descent from the Cross, the Pietà, the Entombment, and the Resurrection of Christ.
pendant
One of a pair of related works of art.
pendentive
One of a series of concave triangular members that support a dome over a square space.
pH
Power of the hydrogen ion concentration measured on a scale of 1–14. The greater the hydrogen ion concentration, the lower the pH. When the pH is above 7 (neutral), the solution is basic (alkaline); when it is below 7, the solution is acidic.
to alphabet PhaseOne
The LightPhase PhaseOne digital back is designed to fit onto a Hasselblad camera in the place of the photographic film cassette. It has a silicon charged couple detector (CCD) that converts radiation incident on the detector surface into an electronic image. This camera is sensitive to the shorter wavelengths of the infrared band of the electromagnetic spectrum (up to 1.1 microns). It produces high-resolution digital images (3120 x 2060 pixels). IR cameras are used in conservation to detect underdrawings and compositional changes below the paint surface of works of art.
pigment
A colorant that, together with a medium, makes paint. Pigments can be
synthetically formulated or naturally derived from minerals, plants,
or animals.
pilaster
A rectangular column set into a wall as an architectural decoration.
to alphabet plaster
A finish material used for construction (ceilings and walls),
sculpture (molds and casts), and decoration. In its powder form, it
is mixed with water to form a paste. Once dry, the mixture forms a
hard solid. It can be mixed from different binders. Frescoes and wall
decorations are typically made from lime plaster, which contains
calcium oxide. Sculpture casts and molds are Plaster of Paris, made
from calcined gypsum. Stucco, which contains gypsum, chalk, or sand,
is used for ceiling and wall decoration.
polytheism
Belief in more than one god.
progress
A model or view of history that predicts not simply that things will change over time but that historical change will inevitably represent advance or improvement. During and after the devastation brought on by the First World War, many people subjected this popular and ultimately optimistic philosophy to harsh criticism.
Psalm 106
Sargent conflated verses of Psalm 106 for his inscription, which reads:
They forgat God their savior which had done great things in Egypt…and they served idols which were a snare unto them Yea they sacrificed their sons and their daughters unto devils and shed innocent blood even the blood of their sons and their daughters unto the idols of Canaan…Therefore was the wrath of the Lord kindled against His people…And He gave them unto the hand of the heathen and they that hated them ruled over them their enemies also oppressed them and they were brought into subjection under their hand…Nevertheless He regarded their affliction when He heard their cry and He remembered for them His covenant.
Puvis de Chavannes, Pierre
(1824–1898) French muralist and painter who decorated many official
buildings in France, one of the most famous being the Panthéon in
Paris.
to alphabet raking light
Illumination used for the topographical study of a painting surface. The painting is illuminated from one side at an acute angle. Conservators use this type of light to observe surface qualities such as undulations and brushwork.
relative humidity
A ratio of the quantity of water vapor in the air at a specific
temperature to the quantity necessary to saturate the air at that
temperature.
relief
Sculpture or ornament that projects from a planar background. These
are further described by the degree of projection from the plane.
“High-relief” forms are sculpted enough to appear partly or almost
entirely divorced from the background. “Low-relief” works project
less than one-half of their presumed depth from the back surface plane.
Renan, Ernest
(1823–1892) French scholar and critic; author of the influential books Life of Jesus, 1863, History of the Origins of Christianity, 1866–81, and History of the People of Israel, 1888–96.
retouching
Paint applied by restorers to mask areas of damage. Unlike inpainting, retouching often extends onto the surface of original paint.
Saint-Gaudens, Augustus
(1848–1907) Irish-born American sculptor widely recognized for monuments in the United States, including the Shaw Memorial (Boston, 1897). He carved some architectural elements of the Boston Public Library.
to alphabet Salon
Juried exhibition of works by members of the Ecole des Beaux-Arts (formerly the French Royal Academy), by the late 19th century usually held annually. For most of the 19th century, people considered the Salon the guardian of the highest artistic standards and the arbiter of taste.
Sargent letter transcription
March 12th 1894To the President and Council of the Royal Academy of Arts, Burlington House Gentlemen— Being desirous of exhibiting in London, before sending it to America, the completed portion of a mural decoration upon which I am engaged, my wish would be to exhibit it at the Royal Academy. I must add that an essential feature of the work is the use of ornament in relief of which there is a considerable amount and which would have to be adjusted to the canvases by myself before they are [nailed] to their place, which I should prefer as high as possible. I am, Gentlemen, Yours faithfully, John S. Sargent saturate
To deepen colors and increase contrast on a painted surface, usually by “wetting” a surface with varnish, medium or solvent. Dry, blanched or dirty paint surfaces that may appear hazy are often described as being insufficiently saturated.
scaffolding
Temporary raised platforms used to gain access to the parts of a structure that are out of reach.
sconce
A decorative wall bracket that holds a lighting fixture.
to alphabet sculpture in-the-round
A three-dimensional work that the viewer can see from all sides.
Sermon on the Mount
The name given to the teaching recorded in Matthew 5:3–7:27 and delivered by Jesus to his disciples and others in the hills of Galilee early in his ministry. The sermon includes the Lord’s Prayer, the Golden Rule, and a series of blessings called the Beatitudes (for example: “Blessed are the meek, for they shall inherit the earth,” and “Blessed are the peacemakers, for they shall be called sons of God”). A similar teaching is recorded in Luke 6:17–49.
siccative
A material that speeds drying, specifically in oil-based paints and varnishes. Lead white and manganese oxide are pigments with drying (siccative) properties.
Sistine Chapel
Papal chapel in the Vatican palace, erected between 1473 and 1481. Many Renaissance artists, including Perugino, Sandro Botticelli, and Domenico Ghirlandaio, decorated its interior. The chapel is best known for the frescoes by Michelangelo (1475–1564) that represent Christian interpretations of scenes and heroes from the Hebrew scriptures on the ceiling (1508–12) and the Christian Last Judgment on the west wall (1534–41). Michelangelo’s frescoes inspired generations of artists.
solubility
The tendency of a substance (a solid material) to be dissolved into another (a solvent).
solvent
A liquid capable of dissolving another material.
Sorrows of the Virgin
There are seven Sorrows of the Virgin, usually represented as seven swords piercing her breast. The Sorrows are the Presentation in the Temple (the Prophecy of Simeon), the Flight into Egypt, the Loss of the Child Jesus in the Temple, the Meeting of Jesus and Mary on the Way of the Cross, the Crucifixion, the Deposition of Christ, and the Burial of Jesus.
spandrel
Roughly triangular wall space between the curves of adjacent arches, frequently used as a surface for decoration.
Special Collections Hall
The third floor of the Boston Public Library housed many of the collections that are now part of the Rare Books and Manuscripts Department. Also known as Special Library Rooms and later, Sargent Hall.
to alphabet specular light
Illumination directed toward a painting from an approximately ninety-degree angle, so that light reflects off the surface directly into the eyes. These reflections, normally avoided in photography, can show subtle differences in the gloss and texture of the paint surface.
stucco
A form of plaster containing gypsum, chalk, or sand. It is often used for ceiling and wall decoration.
substrate
A material, such as a canvas and ground, onto which paint is applied.
support
The structural materials for a painting. For example, these may include a canvas and its stretcher.
surfactant
Also called detergent, dispersing agent, emulsifier, surface acting agent. A compound that breaks down the surface tension between two unlike materials (such as oil and water), allowing them to combine. Surfactant molecules contain a water-soluble (hydrophilic) and a water-insoluble (hydrophobic) component.
to alphabet surface coating
See varnish.
tenting paint
Detached layers of paint (and/or ground) that have lifted up from the surface, forming visible ridges. This condition may be caused by fluctuations in temperature and relative humidity.
tonality
The relationship between different shades of colors used in a painting.
ultraviolet (UV) light
Invisible radiation just below the blue-violet portion of the visible
band of the electromagnetic spectrum. UV radiation causes materials
to "fluoresce," or re-emit visible light. Various colors of paint and
layers of varnish fluoresce differently, allowing for the detection
of areas of cleaning and previous restoration. Recently-applied paint
usually absorbs UV light and appears dark, while old varnish absorbs
UV and re-emits visible fluorescence. Conservators can study this
fluorescence with the naked eye, and it can be documented with
photography. Examination under UV light can sometimes provide
additional information in identifying certain pigments, especially
zinc white and cadmium pigments. UV light is also used in the study
of cross-sections under the microscope.
The short wavelengths of UV radiation can cause pigments to fade and varnishes to discolor with prolonged exposure. Filtering UV radiation out of the light in contact with an object is an important part of the conservation of light-sensitive works of art. to alphabet under-bound
Condition of paint that has a low proportion of medium relative to the number of pigment particles. This condition causes the paint to appear matte and chalky.
underdrawing
A preparatory drawing executed on a canvas prior to painting as a compositional guide. This can be done in graphite, charcoal, chalk, or dilute paint. Conservators frequently detect underdrawings beneath paint layers by using infrared photography or infrared reflectography.
varnish
Coating that protects a painting’s surface, saturates its colors, and provides an even gloss. Varnishes are made from a wide variety of materials, including natural resins (mastic or dammar), synthetic resins (such as acrylic), wax, egg white, and others.
vault
An arched structure forming part of a ceiling or roof.
vulcanized rubber sponge
A flexible, resilient foam of natural rubber made from treated latex. Its many small pores create a highly absorbent surface. In conservation, vulcanized rubber sponges can be used in a dry cleaning technique, since they will adhere and hold dirt without the use of detergents or solvents.
wax-oil formulation
A mixture of wax and oil emulsified in water, and often involving the use of caustic material such as lye or ammonia. These systems with their elevated pH levels are capable of cutting through greasy soiling material. The wax and oil components help to visually revive abraded surfaces by adding a degree of
saturation, and the waxy residue is also capable of being polished to
give the surface a greater degree of sheen.
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