Turning the Scan From Hell into something readable/printable?

[Rob Peters]

I've been converting bad quality scans from various libraries into clean b/w images, using GIMP and simple contrast/brightness commands.
But this one's got me stumped:

https://imslp.org/wiki/12_Short_Organ_P ... nn_Ludwig)

It looks pretty horrible, and to make matters worse, the horizontal lines are so fragile that they vanish when you turn up the contrast. Same thing happens I try to convert to 1-bit B/W.

Does anyone know how to fix this one? Or maybe someone is willing to do it him/herself, it's only 12 pages. My gratitude would be big.

[coulonnus]

Please look at my monochrome version. With the previous versions the average brightness varies and when you want to convert to monochrome you either loose some lines or obtain large black areas when you try to find the right threshold.

Because of this I have converted it with an application of mine. It uses a threshold based on the surrounding area.

[Rob Peters]

Thanks Coulonnus!
It looks a lot better than my efforts already, at least the horizontal lines are visible now.
I wonder if converting to monochrome is the best way to deal with such images though. Keeping them grayscale but fiddling around with contrast and brightness could be another option - and I tried but one runs into the same problems with either the background being too dark or the lines disappearing.