How are emulsion formulae "engineered"
I was wondering how people engineer emulsion formulae.
like kodachrome for example, how did they know what chemicals to process it in?
would it be difficult for me to engineer my own emulsion?
There are a dozen "stickys" at the top of this forum about this subject, written by a rather eminent photographic chemist, that should give you a lot of answers
As pdeeh says, there's a lot of information in the "stickys" and elsewhere in the forum.
With a little care, making a simple emulsion is not beyond the ability of most darkroom workers with a little experience and application.
But commercial emulsion formulae and modern sensitised products generally are the result of many decades of R & D, a detailed knowledge of chemistry and physics, and gradual development and improvement over many years.
Kodachrome was probably one of the most complex products and the history of its original invention is well recorded. The inventors must have had enough knowledge of sensitive materials and colour chemistry to have at least an idea of the correct processing chemicals to start their experimentation, but even then the film and the processing was redesigned and improved over probably some 50 years.
Like a lot of industrial products, Kodachrome manufacture also depended on the skills of the factory operators and emulsion makers. All the data is fully recorded in patents and other published material, but I doubt it could be replicated again without the skills and experience of the workers. (Perhaps a bit like the Apollo moon landings, apart from anything else, so few of the original designers and experienced engineers are still around now that it would be almost impossible to repeat in their original form, even if all the blueprints and information were still available.)
Of course you can not repeat the apollo mission as it was , alloys were different , manufacturing standards , cutting , welding chemicals are old, every detail and its technology is outdated today. Its silly to load every blue print to a computer and want the similar craft with todays standarts. May be today , they can repeat it with 1/3 size of a rocket. When it is impossible to reproduce kodachrome after 5 years, of course it is impossible to do the apollo or MIR.
With knowledge of the basic processes and chemistry that are involved in making a basic photographic emulsion, it's not difficult to "tweak' variables to adjust the finished product. Bear in mind that even a b/w commercial product involves a lot more than just light-sensitive particles: anti-halation dyes, accutance dyes, sensitizers, preservatives, anti-foggant, anti-static coatings, protective overcoating etc., etc., are all combined to produce what we are familiar with as "off the shelf" film. Colour products are extremely complex, and without specific equipment practically impossible to reproduce. It doesn't hurt to try though, if you've the time and money
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It is a lot of fun though!
You can use just about any emulsion for any product, but there is the optimum that gives you something in a given product that makes it the best in tests. When that happens, you know you have something special. Suppose you are trying 0.2 micron AgBrI (1% I) and just for a whim test a 0.22 micron AgBrI(0.5%) and it wows everyone. This is R&D.