Table of Contents
Producing one's own photosensitive emulsion is not a simple exercise of formulation*. To get an emulsion with the expected properties (thinness, sensitivity, contrast…) one must first define the chemical proportions to be mixed (formulation), all the while anticipating the choreography of the preparation itself (definition of a protocol). These two aspects combined allow for a great number of different possible emulsions. The preparatory work boils down to the elaboration of hypotheses, guided by results of one's previous experiments, shared experiments, and the knowledge gathered from numerous scientific studies driven by the past century's flourishing economy around film. Why must we still formulate hypotheses on the preparation of film emulsions if science has already “done it all”? Simply because science, after a phase of fundamental research, was a tool for industry, and the complexity of the actual emulsions of which we are fond and know well is available to us either by the same technology or by added chemical elements (sensitizers, color couplers…). We have to appropriate this knowledge for ourselves to take it out of the industrial sphere - out of the industry which tends to normalize the method of production by automation of certain tasks, thereby eliminating a great number of variables which we, instead, will use to compose and experiment.
Recipe or protocol?
In cooking, we can make cakes of different organoleptic qualities by following different recipes, or, with the same recipe, by using products coming from different sources, using a different pastry chef, or a different kitchen, etc. The recipes followed for making one's own cake at home don't take into account the particularities and constraints which come up as they're put into play. A recipe remains a set of actions performed under ideal conditions. Without wanting to be reductionist: if in the kitchen we often get results which are satisfactory or even better than satisfactory, it's because we don't take many risks in mixing things which are good independently of each other, or, more rewardingly, the Experience acquired in culinary preparation allows the seamless effectuation of a protocol into the particular conditions of your kitchen, and even adding your personal touch. Furthermore, the basics of experience are quickly attained, and we can quickly identify if it was too much butter or if it was the too long cooking time to guide us in correcting our actions for the next time. In our artisanal practice, it's hard to “taste” the products as easily, and getting a clear and solid explanation of the variations observed in any of the properties of our emulsions, properties which are generally multifactorial. Obtaining experience thus becomes a bit more random when we can't get a clear confirmation or refutation of our (conscious or unconscious) hypotheses.
In order to better orient the decisions taken in the elaboration of an emulsion, or to draw conclusions on the preparation obtained to perfect the next, or still yet if you decide to prepare an emulsion in your kitchen using a given “recipe” (though they should not, in this domain, be called that way since they are not yet finished), you should design your material Experience using some of the bases of physics and chemistry which therein reign, and whose principles are mostly understood since you live in this world governed by the same laws, and you perform physics and chemistry daily in similar situations, such as in cooking for example.
In the context of our activities, we'll talk about protocols rather than recipes!
Know thy subject
Know what a photosensitive emulsions is.
Know the steps for producing a photosensitive emulsion.
Following a protocol
Find a protocol, read it, and consider the conditions for implementation
Collecting the necessary material
Some practical advice for what material to use.
Preparing the film base
Finding a support on which to set the emulsion, and preparing it if necessary. How to prepare the film base?
A list of suppliers.
Sharing one's experience
The research, protocols, and results published on wikipelloche are the fruits of passion found outside of any industrial or commercial context, and often out of any institutional context at all. In order to increase the tests done and to learn more from errors, we can share our experience - from the protocol to the results, with observations at each stage - with the rest of the community (in particular, by participating in this wiki).