Process in brief
Collodion process-Poe Boy formula (No ether/No cadmium)
The procedure for the collodion "poe boy", or "poor boy" as some say, is interesting for it does not involve ethyl ether, which is particularly hard to find and use, nor cadmium salts which are harmful to the environment.
The formula is as follows:
to make about 550ml photographic collodion:
to 240ml collodion USP 5% add solvent, that is 300ml ethyl alcohol 96º (other than the product that you can purchase form LabOldTech, you may use pure drinking alcohol that you find in any supermarket)
To prepare the saline solution, dissolve 3 gr of potassium bromide ( KBr) in 6ml of demineralized H2O, and then add 5 gr potassium iodide( KI).
Iodine salt is a little difficult to melt, we recommend to heat the aqueous solution in bañomaria (double bath) at max. temperature 50ºC. Continue to mix until fully dissolved, you might have to (instill some water) add a little water drop by drop, in the end you will have to remain within 8ml saline solution.
If you do not heat the iodine salt it will precipitate because the solution is over-saturated, so when you add it to the diluted collodion it always has to be lightly warm at about 50ºC.
Pour the saline solution into the collodion stirring fast, a white precipitate will form due to low solubility of the salts; you do not need to filter, the sediment will dissolve during the maturation phase.
If you add 3-4 drops of tincture of iodine you will ease and accelerate the maturing process.
The maturation liberates the Halogens (Br, I) contained into the salts you added. This process will transform the silver nitrate, contained in the sensitizing bath, into silver iodide and silver bromide which will make the plate sensitive to light.