The Paterson 35mm Negative Filing System is the most practical way to store negatives.
Allows filing of negatives and contact sheet together
Extra filing sheets available in packs of 25; 120 system for all 120 formats
It is based around a smart ring binder which contains 25 glassine sheets designed to hold negatives in strips.
Each 35mm sheet holds 7 strips of 6 exposures, and each 120 sheet holds up to 4 strips of negatives, the new wider page accommodating all 120 formats.
Paterson 35mm Negative Filing System
25 x Storage Pages