A
Abrasion
Loss of media caused by rubbing or scraping.
Accretion
An accumulation of extraneous matter on the surface of primarily paintings that alters the original design, i.e. dirt, dust, grime, etc.
Acid burn
A dark discolouration to paper due to contact with an acidic mat, board, or wood panel.
After
A term used to date an artwork created up to 100 years after the date given; a copy of a work of the artist named.
Antique
A term used to indicate that an item is at least 100 years old.
Attributed to
In the best opinion of a qualified expert or authority on a particular artist, a work of art is likely by the hand of that artist.
B
Bears a signature
The terms “bears signature,” “bears date,” and “bears inscription” mean that in our professional opinion, these have been added by a hand other than the artist’s.
Before
Used to indicate an artwork’s date that was created up to 100 years before the date given.
Blanching
A term used to describe a milky appearance of varnish often occurring when improperly applied with a solvent.
Bleeding
A colour that merges into another colour usually due to moisture or solvent use.
Bloom
Patches of cloudiness that can appear on the surface of varnished paintings when they have been exposed to damp conditions. It occurs when moisture is trapped underneath the surface of the varnish or when the painting that has been varnished has not fully dried.
Buckling
A term used to describe ripples or ridges in the canvas.
Bulge
A term used to describe a localised swelling in the canvas, usually caused by pressure.
C
Catalogue Raisonné
A comprehensive scholarly listing of an artist’s entire oeuvre, with information including the medium, date, dimensions, provenance, and exhibition history of each artwork.
Chalking
Powdering off of paint due to poor binding medium in the paint when applied or as a result of damage and deteriorating conditions.
Circa (ca.)
Meaning “approximately” or “about”; often used to mean plus or minus ten years from the date given.
Circle of
A term pertaining to a work of art created by another, perhaps a student, in the period of a master artist showing their stylistic influence.
Cityscape
A painting with urban scenery and architecture as its focus.
Cockling
A deformation of a flat support, like paper or fabric, characterised by wavy ripples or distortions, often caused by uneven moisture absorption or drying.
Colour
The perceived hue, tint, shade or value in an artistic work, sometimes used to describe the dye, paint, or pigment material of a particular hue.
Complementary Colours
Two colours that are on opposite sides of the colour wheel. This combination provides a high contrast and high-impact colour combination.
Composition
The arrangement of elements within a work of art.
Cradle
Most commonly found in European paintings, a structure of fixed slats on the back of a panel used to stop warping of the wood.
Creasing
A term used to describe a line or mark made by compression, folding, or wrinkling.
Consolidation
A conservation treatment to re-adhere flaking or delaminating paint back to the support, usually with adhesive.
Cracking
A network of fine cracks that develop in the layers that make up a painting (ground, paint, varnish) during the drying and aging process and due to stress to the support layer.
Age cracks – a network pattern of straight or slightly curved lines usually caused by the movement of the support.
Drying cracks – these resemble an alligator skin pattern and are caused by the application of a layer that dries quicker than the layer below it. This usually affects a layer or two rather than all layers and the support.
Mechanical cracks – fracture lines that occur after the support has taken some sort of impact usually causing an impression on the surface like a dent. A cobweb-like pattern radiates out from the impact.
Crackle
Fine cracks appearing in any of the painting’s layers, usually in perpendicular form.
Craquelure
A general term for a network of cracks usually caused by the shrinking of the paint or varnish.
Crazing
Microscopic fissures that have developed over time and give a hazy appearance to the painting, but they do not expose the surface below.
Cupping
Cracks that look like islands due to intersecting cracks in the painting and other layers of the painting. Because the adhesion to the support is failing, the edges turn upwards.
D
Deckled edge
The natural edge to a sheet created in the process of papermaking.
Delamination
A separation of the layers in a painting between the ground paint and varnish.
Dent
A depression made by pressure or impact.
Dimple
A term referring to any small hollow in a canvas or paper support that has not penetrated through the layers.
Diptych
An artwork consisting of two canvases or panels either hung tightly together or have a set gap between them.
Discolouration
Changes of hue or value often related to a single colour or pigment and frequently found over an entire painting or print.
Digital art
Artwork created or manipulated with digital technology, often through the use of computer programs, artificial intelligence, and electronic software.
E
Enamel paint
A type of paint made from fine pigments and resin that is formulated to be very fluid and dries to a hard, glossy finish.
En plein air
French for “in the open air,” the practice of painting or sketching outdoors to observe nature, in particular the changing effects of weather, atmosphere, and light.
Encaustic
A type of painting whereby wax (beeswax or paraffin) is mixed with pigments and binders for application onto a surface.
Exhibition history
A listing of museum or gallery exhibitions in which a given lot has appeared. Inclusion in important exhibitions may impact the value of the item at auction.
F
Fibre art
Art encompassing a wide range of artistic activities that utilize natural fibres (such as cotton, wool, linen, or silk) or synthetic fibres (such as polyester or nylon) as their primary medium. The practice includes weaving, knitting, embroidery, crocheting, and quilting.
Fixative
A solution of colourless acrylic or vinyl resin and solvent used to protect and prevent smudging of dust-based drawing materials such as pastel, chalk, or charcoal.
Flaking
Occurs when extreme cracking causes paint or ground layers to come away from its support.
Foreground
The area of a painted composition which visually appears closest to the viewer and is followed by the middle ground and background.
Foxing
Refers to the dark brown spots that can appear on works on paper as they age, frequently caused by a combination of mould and metallic impurities.
G
Gouache
A water-based medium similar to watercolour but that dries faster and appears opaque after drying.
H
Hue
A base or dominant colour.
I
In the manner of
A painting made in the style of a named artist but after their lifetime.
In the style of
A painting made in the style of a master, but possibly of a later date.
Inpainting
A restoration process where damaged, deteriorated, or missing parts of an artwork are filled in to present a complete image.
L
Landscape
A genre of painting which features the natural world including trees, mountains and waterways, also the horizontal orientation of a painting.
Lining
A fine linen canvas used to line the verso of a painting when there has been a structural weakness in the canvas and the paint is showing deterioration or loss.
M
Mould
Microscopic fungi that develop and feed on the organic materials in paintings that are mainly created using cellulose-based materials.
P
Palette
A surface or hand-held panel that allows an artist to mix their paints and colours, also referring to the range of colours used within a particular composition.
Panel
A base substrate, usually wood, on which paint is applied.
Pigment
The base component (powder or liquid) which allows for the colour/hue of a paint.
Portrait
A painting in which the primary focus is on the face and body of a model (usually posing before the artist), also the vertical orientation of a painting.
Primary Colour
Primary colours include yellow, blue, and red. These colours cannot be created by mixing other colours.
R
Reline
A process by which old lining (canvas backing) is removed and a second or subsequent lining is added to increase support.
S
School of
A work executed in the artist’s style and possibly by a pupil or follower of the artist.
Secondary Colour
These are colour combinations created by an equal mixture of two primary colours. See also Primary Colour and Tertiary Colour.
Shade
A hue or mixture of pure colours to which only black is added. It contains no white or grey and darkens the colour but the hue remains the same.
Sketch
A simple, quick drawing done without much detail but catching the chief features and a general impression of an object or scene.
Strainer
Strainers are like stretcher bars in that they are used for stretching canvas for oil or acrylic paintings but have fixed corners so they cannot be adjusted after the canvas is mounted.
Stretcher
Stretchers are used to form a rectangular or square support over which cotton or linen canvas is stretched. The corners can be expanded slightly (keyed) to tighten it.
Studio of
Work of an unknown hand, possibly made under the master’s supervision.
Support
Any material on which paint or other media is applied; most common supports are canvas, board, panel, metal, and wood.
T
Tenting
The delamination of the paint and/or ground along a line of a crack. The layers lift upward in a triangular or tent-like structure.
Tertiary Colour
Tertiary colours are a mixture of two secondary colours. See also Primary Colour and Secondary Colour.
Tint
A tint describes a colour that is mixed with white.
Tondo
A round painting (panel) or carving popularised in Renaissance-era Florence and still used as a contemporary art format.
Tone
The intensity of a particular colour or colours in an artwork.
Triptych
An artwork that consists of three canvases or panels either hung tightly together or have a set gap between them.
V
Value
Describes the lightness or darkness of a particular colour; the highest colour value goes toward white, the lowest value toward black tones.
Varnish
A blend of a solvent and either a natural or synthetic resin which is applied to a finished painting as a protective barrier against moisture and environmental pollutants.
Verso
Refers to the back or reverse side of an artwork, such as a painting or a single sheet of paper.
Viscosity
Refers to the perceived depth and thickness of a particular painted hue; in acrylic painting, a gel medium (a binding agent) can be added to thicken paint while water can dilute. In oil painting, an oil-based additive can be utilised for greater thickness while turpentine or another solvent can thin the paint.
W
Watercolour
A painting method in which the paints are made of pigments suspended in a water-based solution. Watercolour refers to both the medium and the resulting artwork.
Watermark
An image, logo, or symbol embedded in a sheet of paper that identifies the mill at which the paper was made as well as the paper type/style, and in some cases, a date.