Framing Glossary

Acid:  A chemical substance with a pH less than 7.0.  Acid can react to paper products damaging the artwork or photographic causing discoloration.

Acid burn: This will occur over time when artwork is framed with none conservation materials, it will cause permanent yellow and brown stains on the artwork or photo.

Acid-free:  This term is used to describe paper materials used in the framing business and consist of a pH around 7.0.  These papers are less likely to harm artwork or discolor over time.  Paper material with a pH below 6.5 or above 8.5 are not considered acid free.

Acrylic:  Used as a substitute for glass, it is an industrial plastic used in the picture framing business.


Archival components: This includes all the artwork components that make up the artwork sandwich.  These paper components are pH neutral or slightly alkaline to help with acidity.  The glazing will have the UV protection.

Artist proof: (A/P) Artist proof prints are outside the regular edition and are equal in quality to the edition and signed as Artist Proof or A/P by the artist.  They were traditionally property of the artist and limited to 15% or less of the edition. These prints are priced higher due to the restricted supply.

Artwork sandwich: This is all the components inside the frame such as glazing, mat board, mount board, filler board.

Buffered:  A process where calcium carbonate or magnesium is added to mat board to make it more alkaline and therefore more likely to absorb acids and other environmental pollutants.

Canvas floater frame: A type of frame used to display gallery wrap canvas.  This frame allows the entire front surface of the frame to be visible.  The color of the canvas wrapping will be somewhat visible in the float space.

Canvas stretching: The process of stretching a canvas over stretcher bars for framing or hanging.

Canvas transfer: A print, photo, or poster image that has been transferred and fixed to a canvas surface.

Certificate of authenticity: Sometimes referred to as (COA) it is a document that certifies that the artwork is an authorized reproduction of the original art piece. It helps to prove that the artwork is not a forgery or unauthorized copy. There are many different styles and formats of certificates. If the artwork is a part of a limited edition run, it will show the total number of prints in the series and what number the print is. These certificates could be signed by the artist or the publisher or the artist name typed in. Other information may include date printed, type paper and printing process.


Conservation framing: Type of framing that keeps the artwork as unaltered as possible while using materials which minimize the artwork’s deterioration by environmental factors.

Conservation grade framing materials: Includes any material used in the framing package that has been designed to minimize the artwork’s deterioration by environmental factors.

Double mat: This consist of two (2) mats (top and bottom).  The bottom mat has an opening that surrounds the image.  The top mat has a larger opening leaving a reveal (lip) on the bottom mat.

Dry mounting: The process of placing artwork on a substrate, such as mat board, foam core etc., using heat activated adhesive in a heat press or vacuum mounter.

Dust cover:  This is the paper that covers the back of the frame and is put on before the hanging hard ware is installed.   This dust cover keeps out dust, insects, and helps reduce fluctuations in humidity, also limits the infiltration of environmental gasses, and gives the frame a professional look.

Encore paint: Encore prints are produced of the same image used to make limited edition prints, these prints are usually smaller and may have the artist signature and title of the print on them, but the artist does not sign each one of them.  They can be produced in any quantity and on any surface such as different papers, and canvas.  


Fabric mat:  A mat that has been covered with some type of textile fabric such as silk, linen, suede or other fabric.  These fabrics are usually adhered to conservation board but the fabrics themselves are not considered conservation quality due to different dyes or inks used in the fabric.

Fading: A gradual change in the color of paper, art, and photos. This is usually caused by light.

Flaw board:  Mat board that has a flaw when manufactured. This matboard cannot be used for window mats but back side of the acid-free type makes a good mount board.

Fillet:  Fillets are thin, decorative pieces of picture frame moldings that are placed inside the frame or between mats.

Float mount:  A mounting technique where the edges of the artwork are left uncovered by a mat board.  This makes the artwork appear to be floating within a frame or matboard window.  Artwork can be mounted on foam core or other substrates without a mat.

Foam core:  Foam core is light, but stiff material used inside the picture frame, usually as a filler board although it can be used for dry mounting or mounting artwork.  This board comes in different thickness and in bright white, black and cream colors.  The acid-free varieties are available for conservation framing.


Gallery wrap:  A modern style of displaying art in which a canvas is stretched so that it wraps around the sides of a thick wooden frame and is secured to the back of the frame.  It is suitable for displaying with or without a picture frame or can be mounted in a canvas floater frame.

Gator foam board:  A heavy-duty, extruded polystyrene foam board this board is stiffer than foam core and comes in 3/16” – 2” thick.

Gesso: Traditionally a mixture of animal glue binder, chalk, and white pigment used as a primer coat on wood picture frames, canvas, and sculpture.  Modern gesso may be acrylic or soy-based and comes in a variety of colors.

Giclée print:  A high-quality fine art print created with an inkjet printer.

Giclée print on canvas:  Prints are printed directly on canvas using high quality inks.

Glazing:  A term used for the glass or acrylic used to cover and protect artwork in a picture frame.

Hinging:  A term used when attaching a mat or print to the mount board.

Landscape Orientation:  A layout that is wider than it is high.

Lignin:  An organic substance found in all vascular plants.  Papers containing lignin give off acids as they deteriorate which can damage art.  Conservation paper made from wood pulp has the lignin removed.

Limited edition print: Limited Edition Prints are sometimes referred to as “LEs.” Artist will create several prints from the original. These prints are usually lithograph prints. After the prints are made, plates or stone used to create the prints are destroyed or altered so no additional prints can be produced. Each print will be signed and numbered by the artist which includes the print number and the edition size (example 5/100). This means this is the fifth print the artist signed of the 100-print edition size. Usually the signature and edition size are in one of the lower corners and can be located on the image or below the image on the border. Limited edition prints are preferred by collectors as their value go up over time.  Limited Edition prints if framed should be framed using the conservation method including UV glass. Limited Edition prints should never be cut, dry mounted or altered from their original state as this would hurt their resale value.


Mat board:  Matboards have a window cut in the center through which the image can be viewed.  In addition to enhancing the look of the print it also keeps the print from coming in contact with the glazing.  Mat boards are available in many different styles and colors.

Moulding:  Molding is the outer frame that surrounds the art package.  This molding can be wood, metal, or other material.  Moldings can be very ornate and decorative, or it can be very simple, also moldings come in several widths.

Mounting:  The act of attaching artwork to the mount board, or display board by using hinges or dry-mounting, or wet-mounting.  

Mount board:  The board on which artwork is mounted upon inside of a picture frame.

Mutli-opening mat board:  Mat board with more than one opening.

Non-glare glazing:  Glass or acrylic with a matte finish etched on one side to reduce glare from lighting.  This glazing is sometimes called reflection control, it is optically pure and may cause a slight loss in sharpness.  None-glare glazing not recommended for more than two mats or shadow box framing.  When framing the matte side goes away from the artwork.

Original art: Art that is produced by the artist before any reproductions are made.

Overlap:  A term that refers to how much of the artwork will be covered by the mat board.  A standard mat window opening will overlap the image anywhere from 1/8” – ¼”.


Open edition print: These prints may have the artist name and title on them, but the artist does not sign each one of them.  Like the encore prints no limit on how many can be produced.

Panorama print:  A picture that depicts a wide, horizontal view, such as a landscape.  Panoramas are significantly longer in the horizontal dimension than the vertical dimension.

Picture frame: An attractive structural support for the artwork, can consist of many different materials, widths, and thicknesses.

Picture frame size:  This is usually referred to as the size of print, or after mounting and matting size.  Picture frames are usually cut 1/8” longer and wider than the size of the framing package, this allows for the framing package to Contrack or expand due to humidity changes.  Most frames have a ¼” wide rabbet to hold the framing package, so ¼” of the framing package will be covered on all sides.  Interior designers and galleries may need the overall size of a frame which would be the dimensions from outside to outside, horizontal and vertical, because they need to know how much wall space to allow.

Ply: A ply or plies is a layer with in a mat board.  Mat boards come in different ply’s such as 2-ply, 4-ply, 6-ply, and 8-ply.  Standard mat boards are usually 4-ply about 1/16” thick. 

Portrait: Portrait would include a head-and-shoulders, bust, three quarters and full-length of an individual.

Portrait orientation: A layout that is taller than it is wide.

Poster or poster print:  A print that is usually mass-produced and intended to be framed as decoration.


Preservation framing: Preservation Framing as defined by the Library of Congress is the appropriate housing to display the intrinsic beauty and interest of an object while prolonging its life by securing the object in a mechanically and chemically stable environment.

Print size:  Sometimes referred to as image size, is the measured size of the actual image, not including borders or paper size.

Profile: A term describing how picture frame moulding looks when viewed from one end.  A picture frame moulding’s profile includes its height, width, contour and rabbet.

Rabbet: The inner lip or grove of a picture frame, which holds the frame’s components, including the glazing, mat(s), artwork and backing.

Rabbet depth: This measurement tells you the height or space you have when installing the framing package.  Some rabbets are ¼” to several inches, this is important if having mulita mats or shadow box objects framed, as you will need enough space depth to frame them.

Rag board:  Mat board, mount boards or foam core that is made from cotton, which are naturally lignin-free, stable and durable.  Rag Board is the best board available for Museum Framing.

Reveal:  A term used to describe the small bottom or middle mat border left visible in a double or triple mat application.  Sometimes the term “lip” is used for the same application.

Reverse bevel:  A regular cut mat exposes a 45-degree bevel toward the artwork showing the mat’s core color.  The reverse bevel makes the 45-degree bevel toward the mat hiding the mat core color.  It gives a straight edge to the mat window. 

Reversible:  Describes the ability undo a framing or mounting treatment, returning the object to the condition it was before treatment.

Riser:  The riser on a stretcher bar is on top and at the back edge of the frame.  This determines how much distance you will have between the canvas and the top face of the stretcher bar.

Sawtooth hangers:  Small metal bars with a serrated (sawtooth) edge that are used on lightweight picture frames.  They are used in place of hanging wire.

Screw eyes:  Screws with a loop at the end and screws onto the frame for attaching hanging wire.

Shadow box frame:  A deep box frame with glass or acrylic in front for displaying personal mementos such as military medals, sport jerseys, and many other objects.

Signed only print (S/O):  Each print is signed by the artist but does not have a limited-edition number on them, these prints can go up in value over time.


Signed and numbered: See Limited Edition Prints. 

Single mat:  One (1) mat whose window (opening) surrounds the image.

Spacer:  Spacers hold the art work off the glazing surface which could stick over time if art work was placed against the glazing.  Spacers can be made of plastic, wood, mat board or foam board.

Stretched canvas:  a canvas that has been mounted onto a stretcher bar support framework in preparation for framing or hanging.

Stretcher bars:  The four (4) pieces of wood material that make up a stretcher bar frame.  It is designed for a canvas to be wrapped and secured around it.

Triple mat:  Same as a double mat except it has a third mat with a reveal (see double mat).

Ultra-violet light:  An invisible portion of the light spectrum.  Ultra-violet light fades artwork and causes paper to become yellow and brittle.  Some of the light sources include sunlight, fluorescent bulbs.  If you are going to hang artwork around fluorescent bulbs or where sunlight can hit it be sure to ask for conservation quality glazing.

V-groove:  A thin groove cut in a mat board top side that exposes the mats inter core, this is for decoration only and is done for the sole purpose of generating extra focus on the artwork.

Wall bumpers:  Bumpers are placed on the two lower corners of a frame, these can be made of felt, rubbery plastic, or a sponge type material and come in different colors. They have an adhesive on the back and are placed on the finished frame package after the dust cover has been installed.  Bumpers provide ventilation behind the frame, helps the frame hang flat against the wall and can help prevent dust lines on the wall.  We now provide two (2) extra bumpers with each frame as bumpers can get dislodged during hanging or transporting.

Weighted bottom:  The bottom border of a mat board is wider than the other borders.  The concept of bottom weighting is since the optical center (the place where a viewer eye spends most of its time) is slightly above the true geometric center in a rectangular region.  Weighted bottoms can be ½ inch, more or less than the other boards, depending on size of framed art.