Preserve your film by developing it yourself. The undeveloped part, the author calls it the Undiscovered Zone. Recently, in the live film work "Invasion of the Undiscovered Zone", the projectionist who screens this undiscovered zone, only an image of bliss. I learned this for the first time in my life. The images of the unseen zone can be seen through reflected light that is not projected onto the screen. The opposite of the screen it's a white image, watch it in one film, polarity reversal.