If you want the film to reticulate, it's really quite easy. Fix the film using a non-hardening fixer. This is one of the keys to doing this as hardening fixer causes the gelatin molecules in the emulsion to crosslink. The emulsion will not swell as much, and the gelatin's melting point is raised by the hardener.(posted 8753 days ago)After you fix the film in the non-hardening fixer, wash the film gently in 80 degree water (you're trying to get the gelatin to swell up). Then, soak the film in 100 degree water for about 2-3 minutes to get the gelatin to really swell up. Don't go any hotter or much longer as the gelatin will start to dissolve in the warm water. Then immerse it ice water for about 2-3 minutes and you should have reticulated film.