>>3121873The film leader is basically wasted to get it spooled. The rest of the film is inside its light tight canister and is only pulled out with the back closed when the film advances after each exposure. If you pull the film out of the canister, it is ruined. If you open the back before you rewind, it is ruined.
For sheet film like this, it has to be loaded into light tight film holders in a changing bag or in a dark room before taking it out with your large format camera. It also has to be unloaded in a changing bag and developed in the dark or it will ruin the film.
