In this period as well, external influences such as intensive use, poor storage conditions, pests, violence and catastrophes threatened a book's chance of survival. Besides, factors related to the way in which books were produced also had an effect: the use of certain types of ink and paper, the binding method.
For a long time these threats constituted a rather constant factor in the margin of the history of the book, but from the middle of the nineteenth century onwards this changed radically because of a drastic development in the production of paper.
Until about 1840, books were printed on rag paper which has a firm structure and, therefore, a high degree of durability. Due to the increase in scale in the production of books in the nineteenth century caused by the mechanisation of the printing process, the demand for paper increased explosively. As insufficient amounts of rags were available to meet this demand, an alternative raw material for paper was sought. After numerous experiments with various vegetable fibres, wood eventually appeared to be the most suitable. Wood, however, contains lignin, a substance which undergoes chemical changes under the effect of air and light resulting in a weakening of the structure of the paper. In addition, the paper manufacturers increasingly used aggressive chemicals, such as alum and chlorine, which led to acidification of the paper and catalysed the decay. This weak wood-pulp paper is extremely vulnerable to external influences, such as poor storage conditions, environmental influences and use.
The effect is that the paper turns brown, becomes brittle and fragile, and eventually decomposes due to internal decay. Research has demonstrated that paper from the years 1840-1950 is in the worst condition with an absolute low in the period 1870-1900.
Already in the nineteenth century there were various indications that something was wrong with the durability of paper. Unfortunately, these warnings went unheeded. Long-term preservation of written text was not an economic factor. Paper manufacturers, printers and publishers had no interest in it. Not until the 1960s did the real extent of the problem become visible in libraries and archives. Of the estimated 200,000 book titles produced in the nineteenth century, more than 165,000 are still present in Dutch libraries, 125,000 of these are threatened directly.
In libraries and private collections books from the seventeenth and eighteenth centuries were surrounded with better care than the contemporary collections. For some categories of printed matter, such as newspapers, popular magazines and trivial reading matter, the preservation aspect played no role whatsoever in either the production or the consumption: they were printed on paper of the poorest quality and were not or only to a very small extent collected by libraries. The fact that, in the nineteenth century as well, no legal deposit library existed in the Netherlands, also played a part in this respect. Despite the large number of copies printed of this kind of material, most has been lost.
