An overcoat is only needed if the film is rolled up on a takeup spool.
It can consist of anything you want to add such as antifoggants, hardeners, matting agents, antistatic agents, tints, dyes.... Well, you get the picture.
Generally, I coated an overcoat even at a small scale, but if we didn't mind the scuff marks and blemishes we just made one pass. Typically, Kodak machines could coat 2 layers with 2 hoppers and a takeup spool. The machine was T shaped with a hopper at each end of the - bar at the top and drying between. Then the film or paper looped down to the long | bar of the T and was wound up.
This is not true of the slide hopper machines or the very tiny machines. P3 was an example of the single ended machine such as in the post above, but there was no loop. The coating was rolled up at the end of the machine.
Last edited by Photo Engineer; 12-26-2007 at 11:36 AM. Click to view previous post history.
Reason: Removed double signature.