Help Enhancing Ancient Manuscript

[MTW613]

I've got a ~1000 year old manuscript (ink on vellum) that needs to be enhanced so its easily legible when printed in black and white.  I'm including an image from a representative page:
Image

I've played around with the GMIC filters and produced the second image at the link above, but I'm hoping we can get it cleaner (it's super dark and all the dirt/damage is still there). In theory, the ink should be a different color set then the dirt/damage and so I was hoping it would be possible to do something like:
1) Use the color picker to identify the ink color
2) Use some tool to select everything within a certain margin of error of that ink color
3) lift it and add it to a white background

I don't know if that's possible or how to do it.  If anyone can help with a guide on what to do (all ideas are welcome) it would be much appreciated.

thanks!

[jacques_duflos]

In your image, I don't see the difference of color between the ink ant other dirt/damage. But selecting pixels according to its hue can be made by the select by color tool :
   

[Ofnuts]

(08-06-2023, 07:57 PM)MTW613 Wrote: I've got a ~1000 year old manuscript (ink on vellum) that needs to be enhanced so its easily legible when printed in black and white.  I'm including an image from a representative page:
Image

I've played around with the GMIC filters and produced the second image at the link above, but I'm hoping we can get it cleaner (it's super dark and all the dirt/damage is still there). In theory, the ink should be a different color set then the dirt/damage and so I was hoping it would be possible to do something like:
1) Use the color picker to identify the ink color
2) Use some tool to select everything within a certain margin of error of that ink color
3) lift it and add it to a white background

I don't know if that's possible or how to do it.  If anyone can help with a guide on what to do (all ideas are welcome) it would be much appreciated.

thanks!

Unless you can find (with the pointer dialog, for instance) even subtle differences between vellum-under-dirt and ink-under-dirt, that you can hope to amplify with suitable techniques, all your attempts at dirt removal will also remove the text.

Usually, these old manuscripts are handled in laboratories that have more powerful techniques than plain photography at their disposal, such as monochrome lighting, IR/UV photo, transparency lighting, X-Ray...

[PixLab]

(08-06-2023, 10:57 PM)Ofnuts Wrote: Usually, these old manuscripts are handled in laboratories that have more powerful techniques than plain photography at their disposal, such as monochrome lighting, IR/UV photo, transparency lighting, X-Ray...

@MTV613, if you don't have access about what Ofnuts told you, I would try different type of photography, like a light board under the vellum with different color lighting, same from above, did you tried with a black light (the one in night club) or aquarium light?
then maybe mixing all those different pictures in GIMP, etc...
The most important part IMHO, in your case, is the photography part.

[rich2005]

well....I can get this fairly easily.

   

Filters -> Blur -> Median Blur (using default values)
Tools -> GEGL Operations -> Color Warp Set To colour to White. Set the Weight to a really large value. Colour pick the From colour and adjust.

50 second demo: https://i.imgur.com/yi59aIM.mp4

You might improve on that, try one of the gmic sharpen filters, but as the other posts, you are coming from a poor starting point.

[denzjos]

An option is trying to make the text more readable with NIK sharpener pro. Can be used in gimp with shellout : 
https://www.gimp-forum.net/Thread-PS-NIK...t=shellout