Here's a fool proof way of reticulating the emulsion!
Process the film normally. Fix using a non-hardening fixer (important). Wash as usual.
Mix some Sodium Carbonate (arm and hammer washing soda), up to 1 ounce per liter.
Water must be somewhere between 100-160°F.
Soak the desired negative in the solution. Once desired effect is obtained, wash in cold water and dry. If
crystals are present on the dried negative, wipe dry crystals off and re-wash negatives.
Higher concentrations give a more wrinkled effect. Higher temperatures accelerate the reaction.
Low concentration at low temperature gives a leopard skin look. High concentrations at high temperature will
peel the emulsion off.
When the emulsion is soft, it is possible to manipulate it with solid objects or imprint textures in it like
Polaroid Time-Zero films.
Drying of the negatives takes longer than average.
I read that rolling a clean tennis ball across the film gives an interesting texture