At the end of the nineteenth century, the demand for paper rose and machines were increasingly being implemented for paper production. This required a simplification of the production process and cataloguing of new raw materials. In 1806, Moritz Illig combined the process of paper making and sizing through the use of rosin and aluminum sulfate (also known as rosin-alum sizing). In addition, Gottlob Keller discovered 35 years later that wood fiber could be used as a raw material in the production of paper. However, these two innovations resulted in a clear drop in the quality of paper. The increased acidity caused a more rapid disintegration of the paper. Age-resistant papers strengthened by the introduction of DIN/ISO – Standard 9706—and which age much more slowly—were not implemented in paper production until the 1990s.
Since 1994, the DLA has been testing deacidification treatments available on the market. In choosing a suitable treatment, different combinations of writing tools and materials place different demands on the procedure. In printed materials, a great variety of papers, ink colors, binding materials and book decorations are emerging. In comparison, the manuscripts at the DLA display a much greater range of writing materials and pigments used by authors, publishers and researchers. Brown iron gall ink, which was replaced over time by differently colored inks and ballpoint pens, can be found among colorful felt-tipped pens, typescripts and more, including carbon copies, copies made via different techniques, telefaxes (for example, thermal papers) and the diverse expressive qualities of diverse printing systems. Among the most common collected pigments, red hues and their variants are the most sensitive in the deacidfication process.
The preservation of original autographs via paper deacidification is a challenge of the near future and is currently being evaluated at the DLA. On the other hand, comprehensive preservation measures are already taking place for the books in the library of the DLA. 77% of the book holdings that come into question pass through the non-acqueous conservation treatments in batches. Through this process, an alkaline reserve in the paper works against future acid buildup.