Numerous references have been made here to the fact that modern gelatins are not the same as the gelatins used in the past for film and paper manufacturing. The so-called "activated" gelatins. Since film production only slowed down about five years ago, I am curious as to why the traditional gelatins used for film/paper manufacturing went away? I know that all modern manufacturers have, I guess, figured out how to use current gelatins, but why did they have to? When did the switch occur?