When you bake a tape, it takes a few years for it to regain the moisture chased out while baked. IOW, you have plenty of time to work with the tape- certainly more than 48 hours.
The reason you have to bake them has nothing to do with whale oil :) Modern tapes are made with polyesters, which can absorb moisture at the ends of broken molecular strands. The water molecule allows the magnetic substrate to come unglued. Baking chases out the moisture so the substrate can function normally.
Older tapes from the 1950s were made with acetate. Acetate does not have the moisture issue, so although they have less performance and break easily, they do store much better.
The reason you have to bake them has nothing to do with whale oil :) Modern tapes are made with polyesters, which can absorb moisture at the ends of broken molecular strands. The water molecule allows the magnetic substrate to come unglued. Baking chases out the moisture so the substrate can function normally.
Older tapes from the 1950s were made with acetate. Acetate does not have the moisture issue, so although they have less performance and break easily, they do store much better.