The basic recipe is divided into three steps. They can be completed one after another on the same day, or divided into separate work sessions up to a week apart, according to time available. The steps are precipitation, washing, and ripening & coating. In addition to the three main emulsion making steps, time must be allocated for glass plate blank preparation, and for drying the coated materials. Drying plates or film can take more than a day if the weather is humid. Cutting film adds an extra step, as does panchromatic sensitizing.
To the list of ingredients we have used so far, add erythrosin B (a.k.a. "erythrosine") for ortho emulsions, and erythrosin and pinacyanol chloride ('PinCl') for panchromatic emulsions, and Yellow #5 food dye if you want to add self-screening to either emulsion.
In addition, I dissolved my PinCl in methanol. That was recommended by the service rep at Lab Depot. It is also soluble in water and in ethanol. What a dye is dissolved in may change its sensitizing range, but that is not something I have pursued yet, and I'm not sure I will—or, at least, not soon. It is, though, a worthy question to answer.
You need a 1% PinCl solution. That is 1g in 100 ml of solvent, or 250 mg in 25 ml solvent. Since there are 20 drops in a ml and you will only use 1-2 drops per sensitizing session, 25 ml of prepared dye will last a long time. Store the prepared dye in a dark amber glass dropper bottle. In turn, keep the dropper bottle in a black plastic bag (or other lightproof container) in the refrigerator. It is supposed to keep indefinitely this way. I don't know whether or not the solvent used influences its useable lifespan.
The erythrosin solution is made to 2% and you will be using more of it. I would buy 1 g and mix it with 50 ml of solvent. It is dissolved in a solution of half distilled water and half ethanol. I use Everclear drinking alcohol. Lab and shop grade ethanol have added ingredients and I have no idea whether or not they might affect the solution.
Making the dye solutions is very easy, but does require attention to prevent getting any dye dust into the air. Both powders are amazingly concentrated. Buy the exact amount you want to mix up and avoid the inevitable disaster of trying to weigh out the stuff.
Have ready and lined up: your bottle of dye, an amber dropper bottle of appropriate size (impeccably clean, of course), a clean glass beaker (about 2x the volume of your final solution), a clean plastic spoon, and your measured-out solvent in a beaker or graduate that pours cleanly. Wear latex or nitrile gloves. Never get your face near the materials as you are preparing the solutions. Wearing a basic dust mask is optional, but prudent.
Carefully open the bottle of dye powder. Add some solvent about half way up the bottle. Carefully swish it around in the bottle. Pour the solution into the beaker. Add a little more solvent to the dye bottle and repeat. Slowly stir the contents of the beaker as you add the remaining solvent—except for a little that you hold back. Pour the dye solution into the amber dropper bottle. Pour the remaining solvent into the beaker, swish it to get most of the last of the dye solution clinging to the beaker, and then pour that into the amber bottle. Wipe out the beaker with a paper towel before you clean it with soap and water. Label the dropper bottle, including the date prepared, the concentration, and the solvent used.
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