Paper Permanence and Longevity
Paper permanence is a very important aspect to consider when creating artwork. Acid is the main factor that affects paper permanence. It deteriorates the fiber, causing brittleness and yellowing.
Fine art paper is tested for its acid content by using a pH scale. Less than 7.0 on the scale is acidic, 7.0 is neutral and greater than 7.0 is alkaline. Acid free papers should have a pH of approximately 7.5.
Artists concerned with permanence should not only use acid free papers, but also consider all the elements that come into contact with the paper. This includes drawing and painting materials, quality of water being used, materials used when mounting and framing, and also the environment.
Some important factors to remember concerning the permanence and longevity of paper and artwork inlcude:
- ACID: As mentioned, acid is the main factor that affects permanence, so if you’re concerned about longevity remember the most durable and long lasting papers are acid free.
- OTHER ART MATERIALS: Paper permanence refers not only to the acidic level of the finished sheet of paper, but also to factors that affect the paper after it is made, like what comes in contact with the sheet (paints, oils, fixatives, etc). Make sure you are using safe materials if you're concerned about longevity.
- LIGHT: Sunlight fades all color. Ultraviolet and fluorescent light accelerates fading. Light energy is converted into heat and a minute amount is absorbed by paper, causing fibers to become brittle. Be sure to protect your artwork from the sun and hang it where it won't be directly exposed to sunlight. Consider installing UV shields on fluoursecent lights to prevent accelerated fading.
- TEMPERATURE: Typically a lower storage temperature of paper makes it last longer (although extreme cold can cause brittleness). The life of paper is doubled with every decrease of 10˚ F. Too hot of a temperature can cause mold. In general, the average room temperature range is safe, and it's best to keep artwork in a place where there won't be a 20˚F fluctuation within a 24 hour time period. For example, a garage may not be the best place to hang artwork if it gets down to 50˚F at night and up to 90˚F during the day.
- HUMIDITY: Too low a humidity increases paper brittleness. Too high a humidity increases the chance of mold. Cycling (temperature/humidity fluctuations) weakens and breaks down paper fibers by causing fibers to expand and contract due to the water contained within them. On average 5% of water remains in a finished sheet of paper after the paper making process is complete, so think of paper as being alive... it can be affected by changes in the environment.
- STORAGE: The main consideration is not to let anything acidic touch your paper. Acid free interleafing can be used to store artwork. Acid free tissue paper is a cost effective option. Glassine paper can also be used, or museum barrier paper. They all prevent acid from touching your paper. Do not use a stiff cardboard container to crate your portfolio as the acid in the cardboard can enter your paper. We’d recommend making a container out of either an acid free illustration board or acid free mat board.