– process of removing dirt and/or discolored
varnish from the painting surface. Cleaning is
an irreversible treatment and one of the most
demanding tasks of painting conservation.
Colorimetry – the science and technique of measuring colours according to objective criteria.
– material (such as gesso or spackle) is
used to replace lost paint and ground so that
the area of loss becomes level with surrounding
Transform Infrared Spectroscopy (FTIR)
– an analytical technique that permits the
classification of a broad range of organic compounds
and some inorganic pigments. An FTIR microscope
permits samples as small as about 10 microns to
be used for this analysis.
– traditionally a lean layer of animal glue
and chalk and/or lead applied to the support to
form a white ground on which to paint.
– subjective term used to describe the relative
amount and nature of mirror-like (specular) reflection.
Trade practice recognizes the following increasing
levels of gloss: Flat (or matte)—practically
free from sheen even when viewed from oblique
angles, Eggshell, Semigloss, and Full gloss—smooth
and almost mirror-like surface when viewed from
– the material applied to a support in order
to prepare it for painting. The term is synonymous
with the "priming." Different types
of grounds can be loosely associated with different
periods and schools of painting.
– the texture created in the paint surface
by the movement of the brush. Impasto usually
implies thick, heavy brushwork, but the term also
refers to the crisp, delicate texture found in
smoother paint surface.
Reflectography – an imaging technique
for studying underdrawing and underpainting (the
preparatory sketch on canvas that precedes the
application of painting). Infrared light penetrates
upper layers of paint and is then absorbed by
the underdrawing. This differential absorption
can then be imaged by an infrared-sensitive camera.
– separation of the paint layer from the
substrate (ground or canvas in this case), often
resulting in distortion or loss of paint.
– a new piece of fabric attached to the
reverse of a canvas painting, providing additional
support for the picture.
– describes a localized area of artist's
material that is missing, perhaps causing a disruption
in the design. Can apply equally to support, design
layers, or coatings.
– a highly magnified image taken
with a camera attached to a microscope.
Light Microscopy (PLM) – an examination
that permits the identification of pigments and
fibers. Pigment particles used for PLM are typically
in the size range of 1–20 microns, or less
than a thousandth of an inch.
light – the placement of a light
source to one side of the painting at a low angle
to the surface, so that the light glances across
the painting. This examination reveals surface
distortions, such as raised paint or undulations
in the canvas.
– the work done by a restorer to replace
areas of loss or damage in a painting. Contemporary
conservation ethics dictate that retouching or
inpainting must be confined to the specific area
of loss and materials used must be reversible.
– to apply a thin layer of semi-opaque paint
over a color to modify it. A scumble is a layer
of paint used in this way.
– a wooden framework that supports and maintains
the tautness of a piece of canvas. Stretcher designs
have been modified throughout the centuries.
light – the placement of a
light source behind the painting. With this technique,
light is transmitted through cracks, tears, paint
losses, and thinly painted areas, thereby differentiating
them from more heavily painted areas.
– ultraviolet (UV) illumination
is used as a scientific aid in the examination
of paintings. Because different painting materials
exhibit characteristic fluorescence colors when
exposed to ultraviolet light, UV illumination
can be used to identify areas of retouching and
to determine different types of varnish.
– a preparatory drawing directly on a ground,
which is subsequently covered with paint. Such
drawings are often executed with charcoal, chalk,
pencil, or paint and brush.
– a coating applied to the surface of painting.
– an imaging technique that is very helpful
in revealing changes that may have occurred during
the different stages of development of the painting.
Pigments containing heavier metals absorb X-rays
more than other pigments and X-radiographs register
these differences, revealing changes of the composition
by the artist as well as losses of original paint.
Fluorescence Spectroscopy (XRF) –
a nondestructive examination tool that permits
the characterization of most inorganic pigments
through the identification of their elemental
Compiled by Piotr Rabicki, Education Intern,
Department of Conservation with assistance from
Chris McGlinchey, Conservation
Scientist, The Museum of Modern Art
Bomford, D., J. Kirby, J. Leighton, and A. Roy.
Art in the Making: Impressionism. The
National Gallery Publications Limited, London,
Conservation Institute. CCI Notes. Ottawa,
D. W. and M. Leonard. Looking at Paintings:
A Guide to Technical Terms. The J. Paul Getty
Museum, Malibu, California, 1992.
E. F., S. Walston, and M.H. Bishop, eds. Matte
Paint, Its history and technology, analysis, properties,
and conservation treatment. A Bibliographic
Supplement to Art and Archeology Technical Abstracts,
Vol. 30, 1993.