You may have noticed that we sell a number of products marked as ?Acid Free?. What does this mean and do you need it?
Here we take a broad look at Acid Free paper - it's history, it's making and why we need it.
Paper ? A Brief History
The basic process of paper making has been around for a long time. It is reputed to have first started in China in 105AD, where they mainly used textile waste, known as rag, as the raw material for their papers. Although the making of Papyrus (like a thick paper) and Amate (a type of bark paper) had been around before this time, they are not considered to be a true paper.
Paper making continued throughout the world, spreading to Islamic states by the 8th Century and then to medieval Europe by the 11th Century. Improvements to paper making were to come as late as the early 19th Century when Henry Fourdrinier and his brother commissioned the Fourdrinier paper making machine. This machine revolutionised the way the paper was made, as it produced continuous rolls of paper using wood pulp. This wood pulp paper was acidic and was prone to disintegration over a period of time through a process known as slow fires (acid decay). From the mid 19th Century Acid Free papers first made their appearance to address this issue.
What is Acid Free paper?
Acid Free paper is a paper which has a PH of 7 or slightly higher (making it PH Neutral or Alkaline). Acid in the paper comes from a chemical compound called Lignin, which occurs naturally and basically holds wood fibres together. Lignin itself is not acidic, but over time, as the lignin deteriorates it gives off an acid and as it does so, the paper will turn yellow and become brittle.
Just note that not all Acid Free papers are lignin free and the lignin in an ?Acid Free? paper will still deteriorate over time- although this period of time is generally many, many years and will still outlive most of us! Acid Free papers are manufactured to eliminate most (if not all of, in some cases) the lignin, as well as to neutralise the acid present during the pulping process. This is done by two processes, one being to separate off the lignin present, by the use of chemicals. The next process is where the acids already present in the wood pulp are neutralised with the use of an alkaline such as Calcium Carbonate. Sometimes from here a process called Buffering will be carried out, where the alkaline is added in excess to prevent future Acid attacks, either from any lignin present or from external influences that create acid formation (such as atmospheric Sulphur Dioxide).
Choosing an Acid Free paper allows for a greater lifespan of images and documents.
Acid Free or Archival Paper?
Archival Paper is used for documents and publications of significant value. Archival Paper is always acid free. Often Cotton Rag is used for Archival Paper as it is not made from a wood based pulp, and is therefore not naturally acidic.
Archival paper is sometimes broken down into either Archival Grade, also called Museum Grade and this is a Cotton Rag Paper made from Cotton pulp; and Conservation Grade which is an acid free paper made from a wood based pulp, but treated to raise the PH levels.
Archival papers are often a firm favourite of Fine Art photographers and those selling images because of the exceptional lifespan under ideal conditions (200+ years).
Here at GDS we sell a huge range of Acid Free and Archival Papers. We do a range of GDS brand Acid Free fine art papers, which can be found HERE.