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Mountboard.

Updated: Sep 26, 2023



Mountboard and framing implements

What is Mountboard?


Simply put, mountboard is the material which comes into direct contact with your print. It is made of paper or cotton.


Your print will be attached to a sheet of mountboard that sits behind it (commonly known as backing board). There will be usually be another piece of mountboard laid on top of print. A window will be cut out of this mount to reveal the print, hence the term window mount. The two pieces of mountboard will be hinged together along one side and the print sits in the middle, like the filling in a sandwich. The window mount also creates distance between the print and the glass. This is important so that the print does not touch the glass as over time, this will be detrimental to the print. If there is no window mount as, for example, in float-mounted prints where the edge of the artwork is on view, a deeper frame with spacers or fillets are used create a gap between print and glass.


Cotton or Paper?

Cotton mountboard (also known as ragboard or Museum board is the highest quality of mountboard but comes at a price and so is usually limited to high-value prints and to Museums and galleries. The majority of mountboard used commercially is made, therefore, from paper fibres. However, these vary greatly in quality and it is useful to have some understanding of the different grades when choosing a mountboard for your print.

All papers contain lignin, part of the structure of wood which binds cellulose fibres. Lignin, although not an acid itself, is chemically unstable and sensitive to light and heat. As it breaks down it gives off acid as it deteriorates. There are various ways to reduce or delay the damaging effects of lignin in mountboard and because of this terms such as 'acid-free' and 'conservation-grade' are variously used to describe mountboard. But these terms can be misleading. 'Acid-free' usually indicates that the mountboard has been treated to give it a pH value of more than 7. This is either done by the addition of alkaline fillers - known as buffers which raise the pH of the board or by chemically de-lignifying the pulp which significantly reduces the acid-forming compounds in the pulp. Neither method will render the board completely free of acid in the long term though the second method is considerably more effective than the first. Though the addition of alkaline fillers might result in an non-acidic board at the time of manufacture, over time chemicals from the atmosphere of from processing may well lead to the formation of acid. The term 'acid free' is therefore misleading and we avoid using it.


Standards of Mountboard.


TrAcery Prints & Framing uses Mountboard Quality Level 1 and 2.


Until 2019 there were three standards of mount board, Cotton Museum, Conservation and Standard. Following a review these three levels are being replaced by four levels, 1-4, with 1 being the highest grade and 4 the lowest. These changes are being phased in to allow current mount board to be used up and full compliance will not be mandatory until 2024.


Mountboard Quality Level 1 (was Cotton Museum). Often used names: Museum, Cotton, 100% Cotton, Rag

Mountboards with all parts made from 100% cotton fibres

Best for Museum and Conservation level framing but can be used for all levels of framing. The board must be made from 100% cotton fibre.


Mountboard Quality Level 2 (was Conservation) Often used names: Conservation, Alpha, Alpha cellulose

Best for Conservation level framing but can be used in any framing except Museum level

It is noted that some organisations work to technical specifications for purchases of high quality mountboard. Such specifications are often met by both Level 1 and Level 2 boards


Mountboard Quality Level 3 (was Standard) Often used names: White Core, White Core Plus

May not be used for Museum or Conservation levels of framing. Can be used for Commended level framing and below.


Mountboard Quality Level 4 (was Standard) Often used names: Standard, Cream Core

Best suited to low quality framing.

May not be used for Museum or Conservation levels of framing. Can be used for Minimum level framing. Any boards that do not meet Level 4 as a minimum specification are considered unsuitable for use within the Guild’s Levels of Framing.



The Quality Standards for Mountboard specified by The Fine Art Trade Guild take into consideration:


  • Pulp composition and purity, testing methods, pH value, alkaline reserves and fillers

  • Facing paper colourants, bleed, lightfastness, abrasion resistance, testing methods; sizing

  • Lamination adhesives

  • Moisture content

  • Board markings

  • Thickness and Board Dimensions

  • Quality Control

  • Packaging

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