When a drop of ink or watercolour paint is placed on wet paper, rather than uniformly diffusing in all directions it forms tendrils which rapidly expand out from the spot.
Why is this and what is the chemistry or physics occuring?
This video may further show the type of thing I am referring to
https://motionarray.com/stock-video/black-silver-tendrils-pack-216423
It appears that the pigment solvent forms discrete channels outwards through the water. I wondered if this might be a surface tension interaction or something else.