[Gimp-user] Enhancing old document

[AlanR <forums gimpusers com>]

I am trying to use GIMP (2.8.10) to make some indistinct annotations on a
medieval manuscript more legible.  Typical of the published images of its pages
is http://ica.themorgan.org/manuscript/page/35/159535

Examples of the scrawled additions I am trying to enhance are those in brownish
ink after the end of the main (blackletter) text, and across the foot of the
page.

So far I have tried Unsharp Mask (including varying the parameter settings);
several of the colour adjustment tools (including the interesting but drastic
Auto > Equalise); and Rob A's high-pass filter.  All of these are some help, but
I'm still looking for something better - and as a relatively inexperienced Gimp
user, I'm concerned that I don't have a good enough understanding of the problem
to pick the right tools.

Can anyone help, please?  I would be really grateful for any and all
suggestions.

Thanks, Alan

PS Ideally we could do with higher-resolution images to begin with, but as I
don't have access to the original manuscript I have to work with those available
on the web.
 

-- 
AlanR (via www.gimpusers.com/forums)