All of them agreed that all of the texts had been written by the same person, and that person's handwriting was the same as that in the comparison sample. Astonishingly enough, the Hitler diaries appeared to be authentic. However, forensics tests on the paper and ink showed otherwise. Paper is generally classified according to the materials in its composition. They differ according to additives, the presence or absence of watermarks, and the surface treatments used, such as heat or resins.
Specialists can determine the date when a particular type of paper was introduced.
The West German police put the paper under ultraviolet light and found that it contained an additive that had only been put into paper since 1954. The threads attaching the seals contained material manufactured after the war, and the type of ink used had not been available at the time the diaries were purportedly written. Then a test was used on the ink that involved the evaporation of chloride, and this proved that the documents had been written within the past year. In addition, an analysis of the contents revealed a host of historical inaccuracies, apparently overlooked in the magazine's attempt to keep the scoop a secret until publication. One distinguished historian of Hitler's regime, Hugh Trevor-Roper, had actually vouched for their authenticity.