American History

Kodachrome and Agfachrome were essentially B&W film in three layers. Each layer was exposed to a different color light, ie, red green and blue. The silver grains were then bleached out and replaced with a dye. The upside was the dye was almost as permanent as silver, the downside was that the film had to be developed three times. The process was expensive as you can imagine.

B&W film was much faster, as in could capture images in poor conditions, and permanent. Properly processed a B&W print will yield useful information after 2000 years. If Jesus was a real person and if we had a B&W snapshot of him his likeness would still be recognizable.

Later color processes were terrible for permanence, only lasting a few years before losing color and fading.

Modern digital imaging is about as permanent as it gets as it's just ones and zeros that can be stored in a myriad of ways. The actual pictures printed for display will last about 30-50 years depending on how they are displayed BUT the 1s & 0s will last to infinity and can be reproduced without degradation.