The search for the perfect drawing paper, part 2:
As an artist you are likely to take an interest the paper you’re using. If you don’t, you should. It’s important for several reasons:
Ease of use
Duration of work
Scale of work
The first post in this series was about the importance of your choice of drawing paper in relation to your drawing style and process. This post, the second part of this mini-series discusses archival concerns and conservations issues.
The longevity of paper is a serious concern for the artist who values their patrons because poor quality paper will quickly become yellow and brittle. This is easily demonstrated by leaving a newspaper in sunlight, like a window sill or vehicle parcel shelf for a few weeks.
As an artist I need to use the best papers that I can to ensure that I can sell my work in good faith, knowing that those who buy it will be able to keep and enjoy my works as long as they might wish to do so. For myself I often wish to refer back to earlier works and studies without worrying if they will disintegrate.
The longevity of paper is influenced by several factors; paper selection can quickly become a complex issue for artists. The key factor is acidity. The less acid the better. Acids are introduced from a variety of sources:
Common constituents of paper include cotton, wood pulp, cellulose, plant fibres or recycled paper.
Papers made from wood or other cellulose plants typically contain Lignin, a non-cellulose component of plant fibres, which produces acid as it breaks down. Lignin naturally breaks down over time but this process is accelerated by heat or light.
Some paper-making processes use sulphuric acid, although these processes are largely being replaced with acid-free or alkali based processes. The term acid-free normally refers to paper that is produced in a process that does not add additional acids to the paper pulp.
The fibres used to produce the paper can be pulped mechanically by grinding, or chemically, using heat and the action of various chemicals. Lignin and other impurities are usually removed through the chemical pulping process. Paper produced in this way is sometimes referred to as wood-free, since the wood impurities have been removed in the chemical process.
You may also have seen the phrase, ‘buffered’, or ‘alkali buffered’, this refers to the addition of calcium or magnesium carbonate during production, added to offset the acids that would be produced by the paper.
The conditions in which the paper is kept are also very significant. This is the reason why museum galleries control light (especially daylight) and humidity levels so closely, since increasing either of these will incease the rate at which the paper deteriorates.
Paper can also be exposed to acids in the environment, like sulphur dioxide or other air pollutants, or through handling, from the oils on your skin (even when clean). This is one reason for the white cotton gloves you may have seen conservators wearing.
Cotton does not contain Lignin and therefore does not produce acid in this way, so papers made from 100% cotton or cotton rag are considered to have much greater longevity and are often termed, ‘archival’, or ‘conservation grade’.
There is an ISO standard: ISO 9706 Information and documentation — Paper for documents — Requirements for permanence which specifies the requirements for a paper to be called permanent, however it is based on mechanical rather that visual requirements relating to the longevity of paper and so is not entirely relevant to artists papers. This issue is discussed in detail in an article from RK Burt, paper merchants.