Many things

[David V. Corbin]

>>> 
>>> yes, it is information loss.  scanning bilevel is a much 
>>> worse information loss.  scanning at 300 dpi, or 600 dpi, 
>>> or 1000 dpi is information loss.  viewing the document on a 
>>> CRT is information loss.
>>> 

And if one really wants to get down to low levels, simply exposing the
original to the lamp of the scanner is information loss......

[Not that this matters for the vast majority of documents, but I would not
want to use a standard scanner on a really valuable [old] document
thoushands of times.......]