Gimp generated "paper marbling"

[rich2005]

First thoughts and a few minutes experiment and a couple of functions I might use once in a decade



Arrived at that using - Fractal Explorer Filters -> Render -> Fractals https://i.imgur.com/uN3QMSC.jpg

Then one of the gmic (experimental section) filters 'Joan Rake Random deformation' https://i.imgur.com/uVLttVK.jpg Unfortunately the preview does not reflect the result. I suspect better with smaller images.

gmic_gimp_qt from http://www.gmic.eu

There will be other ways, the best way with Gimp is experiment.