 For those interested in patents
I have been asked a lot about the patents related to film making and coating, so here are some of the ones you might find quite interesting.
1. Coating - USP 2761791
This discloses slide coating and shows the design of several types of coating hoppers in current use. Unless upgraded with rather expensive equipment, second and third tier companies do not use these types of hoppers.
2. Emulsion Making - USP 5132203
This shows how to make a graded iodide t-grain emulsion. I worked with one of the inventors during the development of this type of emulsion, when I was working on the emulsion design program and model.
3. Dopants in Films - USP 5360712
This describes what chemicals are added to modern films to get good speed, curve shape, latent image keeping and reciprocity failure. (that is if you follow the crumb trail laid out here)
4. Color Films - USP 5302499
This describes the organic chemicals and emulsions needed to assemble a modern film. It is up to you to pick out the useful chemicals (wheat from the chaff) and to follow the trails again laid out.
There are a lot more patents than this, such as those describing control methods, algorigthms, process control equipment and mixers to name a few but this is enough for now. It pretty much covers all aspects of film making from start to finish.
Remember, a patent only needs to disclose what will help a person "skilled in the art", and so a patent can mislead you if you do not understand the basic underlying principles, or if you don't follow the numberd dots.
This has been a particular difficulty trying to explain photographic engineering sometimes.
Enjoy.
PE | 
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