Glossary of Picture Framing Terms

Acid Damage - Cheaper, and particularly older, framing techniques use or used material that contained acidic chemicals.  As pictures and artwork tend to remain in the same frame for years, over time, the acid can leach out and damage the artwork.  This manifests itself as small dark spots that run through the picture.  If the picture has been framed for a very long time, sometimes these spots become larger.  Today, there are techniques available to remove the marks and good quality framers use acid-free framing material to prevent acid damage.

Acrylic - a type of glass substitute which is a resin perceived as a high quality clear plastic.  It may be used instead of glass in a pictureframe but more commonly is used for frameless display either for sandwiching artwork in between two sheets or to mount artwork to the back of it.

Acrylic Paint - a type of oil-paint substitute with a similar viscosity that uses water as a solvent which makes it relatively quick drying.

Aquatint - a type of etching in which a powdered resin is used to reduce the level of etching achieved over specific areas of the plate in order to provide a tonal effect.  See also mezzotint.

Artwork - A generic term used to describe a piece of visual art which may be of many different types: drawing, etching, painting, collage, graph, photograph, lithograph, print, watercolour or cartoon.

Bevel - A slant or angle on a surface.  In picture framing, it is most commonly the edge cut in a piece of mountboard to form the aperture through which the image is viewed.  The bevel exposes the ‘core' of the mountboard to view.  Most commonly this is white and known as ‘whitecore' but redcore' and blackcore' are also available.

Blackcore - A mountboard (mat) with a core that is coloured solid black.

Board - this is board which is generally used for oil painting.  It is available in a variety of forms, a simple hardboard such as might be used in the building industry, a specialist artboard where the surface of the hardboard has a texture specifically designed to take oil paint or canvas-wrapped board which, as the name suggests, is hardboard with canvas material wrapped and glued to it to provide a 'stiffer' canvas surface on which to paint.

Box Frame - a frame generally made to accommodate a three-dimensional object.  Commonly, a box frame is used to frame sports memorabilia.

Brilliant Cut - this term, normally associated with diamonds, is also used to describe mounts which have been cut in an unusual decorative fashion.

Canvas - A heavy, coarse, closely woven fabric of cotton, hemp, or flax and traditionally used for the sails of ships and yachts, tents and bags.  For painting purposes, canvas material is stretched over a wooden frame to provide a taut flat surface on which to pain.  Canvas is particularly good medium on which to paint with oil paint because of its texture.  Traditionally the stretched canvas is 'sized' or 'primed' before painting starts.

Conservation - the process of preserving an object for posterity.  In picture framing this is very relevant as an item can remain framed for many years.  This means that the materials that are used in framing need to be free from any residual chemicals that might harm the artwork.  The term 'Conservation' also denotes a specific type of mountboard (mat) that has had any harmful chemicals reduced to a low level.  For very delicate artwork, or for artwork of very high value 'Museum' type mountboard (mat) should be used which has no chemical residue.

Core - The central 'filling' of a piece of mountboard (or mat) that provides its strength.  The colour of the core is the colour of the bevel that borders the aperture through which the artwork is visible.  See also: Blackcore, Redcore and Whitecore.

Dry Mounting - This is a process in which very large or very delicate pieces of artwork are fixed under a combination of high temperature and reduced pressure to a substrate.  The idea is to give them greater rigidity and strength so that they maintain their shape when framed.  It is particularly relevant for large posters.

Etching - an etching is the term used to describe a print that is made from an etched metal plate.  The plate may have been etched chemically or physically and the grooves that remain hold sufficient ink so that when the metal plate is brought into contact with a sheet of paper, the ink is transferred and the print is made.  See also aquatint and mezzotint.

Foxing - see Acid Damage.

Frame - An open structure used to enclose or define an area.  Generally a frame is a structure upon which, to which, or inside which, other components are added or affixed.

Giclée- a term used to describe a digital print made on an ultra-high resolution inkjet printer.  The name comes from the French word 'gicleur' which is a word that describes an individual who squirts liquid through a nozzle.

Gouache - This is a type of painting that is similar in appearance to watercolours.  Traditionally it is a paint that has been mixed with Gum Arabic to give greater opacity although there are gouache inks as well.  Gouache work needs to be treated as a watercolour.

Gum Arabic - a naturally occuring substance from two specific species of African Acacia tree used as a binder for watercolour painting.

Mat - US/Canadian usage only - see Mount.

Mezzotint - a method of etching in which the metal plate is covered in great numbers of small indentations to hold ink.  Conventional etching then provides delineation but the artist is able to modify the amount of ink held by the plate by filling the small indentations with varying amounts of resin thus providing control over light or dark.

Moulding - This is the term used for the material used to form the rim of a picture frame.  Traditionally mouldings are made from timber with a vast range of finishes applied to it.  Comparatively recently, metal, particularly aluminium, has been introduced and also resins and plastics which provide the ability to minimise the width of the moulding visible from the front of the picture and to offer a wider range of ornate mouldings more economically.

Mount - a carefully crafted sheet, generally of card, that fits between a piece of artwork and the glazing of a framed picture.  Although a mount enhances a piece of art its primary purpose is to protect the artwork from damage.  The small amount of air between the glass and the image helps to protect against condensation, mould, fungus and mildew.  A fundamental feature of a mount is the bevel which sets off the artwork to best effect.  Valuable artwork should always be protected by a mount.

Mounts should always be properly made of specially developed mountboard (q.v.).

See also washline, blackcore, redcore, whitecore and ‘brilliant cuts'.

Mounts may be single, double or triple.  The number refers to the number of sheets of mountboard that are used to create the mount.  An upper mount has a wider aperture than a lower mount thus exposing a small amount of the lower mount to view.  This can be used to great effect as the two boards are visually separated by the bevel of the upper board.

The mountboard from which a mount is cut may come in a variety of thicknesses although most regularly it is 1-2mm thick or ¹/₁₆".  It is possible to create a powerful visual effect by using an extra thick mount which causes the bevel to be extra wide.

The term should not be confused with the verb 'to mount' where a piece of artwork (generally very flimsy or very large) is 'glued' to a stronger, stiffer substrate material.  This process is generally known as Dry-Mounting.

The word 'Mount' is really only used by the British.  In the US, the equivalent term is a ‘mat'.

Mountboard - the basic material from which a Mount (q.v.) is cut.  The board is generally made from unrefined wood pulp which is then faced with a paper which may or may not be coloured.  The most important property of mountboard is its chemical content because an artwork usually remains in a frame for many years and over that extended length of time, any chemical that is resident in the material very slowly leaches out and can attack the artwork that it is supposed to be protecting.  There are three main qualities:

• Standard
• Conservation, and
• Museum

These increase in price and have correspondingly fewer chemicals within them.  Conservation mountboard should always be used, with Museum for extremely high value items.  Conservation and Museum quality board both have the harmful chemicals reduced.  In Museum, they are reduced almost to zero.

A major feature of a mount is the bevel which exposes the ‘core' of the mount which may be white or coloured - see whitecore, redcore and blackcore.

Mounting - a process used to display artwork.  There are two distinct types of mounting which should not be confused with one another.  The first is to apply a mount as part of the picture framing process.  This means sandwiching the artwork between two sheets of specialist card with an aperture cut in the upper one to reveal the artwork.  This process is intended to prevent contact between the artwork and the glass - see Mount.

The other process is also referred to as mounting but more correctly is Dry Mounting.

Oil - Colloquial term for 'oil painting'.

Oil Paint - a paint in which the pigment is held in an oil-based solvent.  Traditionally, the oil is walnut, linseed or poppy and is slow drying which enables the artist to rework parts of the work with relative ease.  Oil Paint was used by artists who are considered the 'Old Masters'.

Oil Painting - a picture painted on canvas or board using oil paint.

Picture Frame - a Frame (q.v.) which forms a border surrounding and protecting an image or document to enhance it and to provide a mechanical means of support either for hanging or for standing the item in order to display it to best effect.

Print - a term used to describe many different types of printed artwork.  Traditionally a print is made from an etched plate but copies of original artworks, whether modern digital copies or conventional printed copies are also called prints.  Limited Editions or Open Editions are always some form of print.  See also Screen Prints.

Redcore - A mountboard (mat) with a core that is coloured solid red.

Restoration - the act of repairing and cleaning a picture or a picture frame to return it as closely as possible to its original condition.  Generally restoration applies to oil paintings but watercolours, prints and other types of artwork can all be restored.

Rim - the 'frame' part of a picture frame.  The sub-assembly which consists solely of the bits of moulding and the glue and fixings which hold them together.

Serigraph - see Screen Print

Silk Screen Printing - see Screen Print.

Screen Print - a method of creating an image on paper, fabric or some other object by pressing ink through a screen with areas blocked off by a stencil. The technique is used both for making fine art prints and for commercial applications, such as printing a company's logo on coffee mugs or t-shirts.  Traditionally screens were made of silk fabric because the thread from which they were made was very fine but most modern screen-printing is done using synthetic fabrics.

Undermount - When a mount is used in the framing of a picture, the artwork is sandwiched between the mount (which remains visible once the frame is assembled) and the undermount behind it.  Undermounts are traditionally made from mountboard material.

Varnish - varnish is applied to the surface of an artwork to protect it from damage.  Traditionally it was applied by brush but today is often applied by a spray.  Varnish may deteriorate over time.  Older oil paintings may become very dirty and it is generally the varnish which is dirty and not the picture itself.  Old varnish sometimes manifests itself as 'crazing' on the surface.  Old varnish is often removed as part of the process of cleaning or restoring a picture.

Washline - a decorative line applied to a mount (mat) to enhance its appearance.  Several washlines are generally applied to a single mount.  Click here to go to our specialist mounts page.

Watercolour - a painting technique in which the paint colours are supplied in tablet or powder form.  Water is used to transfer the colour to the paper.

Whitecore - A mountboard (mat) with a core that is coloured white.