(03-18-2019, 10:08 PM)TuxfordC Wrote: Herewith a unprocessed jpg image of the original page. The previous sample had been processed as I thought that if I could alter the staining to a primary colour then removal might be possible with GIMP.
Might just desaturate and adjust levels if you aren't concerned about color.
Colors > Desaturate > Desaturate (I used the Value (HSV) mode)
I didn't adjust levels as not sure what you were after but it could brighten the page considerably and darken the text, or leave it as is to show the age without the coloration. Still need some sharpening as well.
Here is you other image using the Luminance setting