[Gimp-user] tips on enhancing text written in pencil

[James]

Hi. I have an elderly friend whose father kept a diary during WW2. The diary
is written in pencil on poor quality paper that has yellowed considerably with
age. The text is still pretty legible but as time passes it will become less
so. I decided I could photograph pages of the diary and enhance them using
Gimp. The final result should be something that can be printed out on a
computer printer, i.e., greyscale/b&w. I took the photos in color, thinking
I'd have more manipulation options, then could make the images greyscale.

I'm not any kind of gimp power user or anything--I usually just feel my way
around the program and usually get it to do the fairly simple graphic
manipulations I want. So far, that method has not worked well for this
project. So I'd like to ask some tips here on accomplishing the goal I'm
after. Ideally, I'd like all the yellowed paper that forms the background of
these images to turn as close to white as possible, while all the pencil text
should be as close to black as possible. Can anyone point me to things I can
try under gimp that will help me accomplish these aims?
-- 
James