Gudrun,

           The likelihood of any OCR processor being able to recognize hand-written script is very, very small.  This is all the more so if/when fading, water staining, margin notes, above-line insertions, strike-throughs, and the like are involved.  All of the previously mentioned items are incredibly common in old hand-written manuscripts.

           I can't imagine that a personal diary would be written in a hand that's nearly consistent enough for OCR to recognize.  Since we're talking about Old German here I doubt that there are many general-purpose OCR engines that would work with that language, even if it's in actual print format.  I do not recall Tracker Software having any Old German OCR engine.
--
Brian

     Is it progress if a cannibal uses knife and fork?  ~ Stanislaw J. Lec