Article about: Many people wonder why old paper items turn yellow with age, or perhaps why they transmit their distinctive odours. The answers lie in the different ways in which the papers were manufacture
Many people wonder why old paper items turn yellow with age, or perhaps why they transmit their distinctive odours. The answers lie in the different ways in which the papers were manufactured, and also the life of the paper.
Old paper items often appear yellow/brown due to a high concentration of a dark substance known as lignin in the paper. Over time, this causes the oxidation process. Lignin is the stuff that helps trees stand up, i.e. it keeps them stiff (no 'wood' or 'viagra' jokes please!). Without it, trees would never reach the great heights that they do. It also darkens the paper over time, especially when left open to the air, or in sunlight as both speed up the process. Cardboard has a higher concentration of lignin, resulting in the stiffer and darker composition.
Mills often used chemicals to clean up the lignin content, thus producing a paler, finer quality paper, which doesn't change colour in the same way as regular standard paper from the period does. This often results in period documentation appearing too new, and unbelievable to some collectors, when actually, it is just the composition of the paper that has preserved the document.
Newspapers on the other hand, are at the other end of the scale. This is because when newspaper materials are produced, the raw material is untreated resulting in a paper product that after just several hours of exposure to air and sunlight, already displays the beginning of the colouration process.
The smells of old paper items add character to an piece, and this can only be achieved over time. Reproduction pieces simply don't have the history of microorganisms contaminating the paper, together with the resulting smells of the oxidation process, and that is why they won't give off the distinctive aromas that period documentation will.
Below are a few images of period documentation, including a national newspaper, birth certificate, concentration camp prisoner's letter and finally an NSKK document. They display the features of the varying paper qualities.
The colouration of old paper items
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