said by Hayward0:From the B&W era, but interesting document of how the whole technology workes in both chemistry and mechanics.
Other than having more steps color is handled pretty much the same way, expose and develop a color negative and from that print color positives.
The second half mechanisms of the process (already much automated) much the same today gets more interesting.
The printer shown in the movie is a drum printer, and that is the same method still used today, the negative travels on sprockets around the exposure drum facing a light source within the drum, the un-exposed positive is then wrapped over the negative where it is exposed by the light passing through the negative.
In 35mm the perforations in the negative have what are called short pitch, while the positive has a long pitch, this pitch change compensates for the fact the positive is traveling a larger circumference around the drum than the negative.
The negative perforations are also shaped differently then the positive perforations, the negative perforations are designed to provide for a tight registration in the pulldown of the camera, while the positive perforations are designed to prevent tearouts from being run through a projector multiple times during its lifetime.
One type of perforations is known as the Kodak Standard, KS or positive perforations, the other type of perforations where known as the Bell & Howell, BH or negative standard.
Wayne