Why did founding ceremony leave only a part of the image?

The Soviet photographer who was authorized to shoot the founding ceremony documentary accidentally burned the film. After returning to China, he was severely punished by Stalin and sent to Siberia to serve his sentence.

Zhou Enlai heard that all the negatives were on fire. After a loud cry of "Ah", he was silent for several minutes in pain. Fortunately, our own photographer who came from Yan 'an and experienced the test of war shot a black-and-white documentary, which preserved the precious scenes of founding ceremony. That's why founding ceremony left only a few fragments today.