I've been using the formulas published in the Crawford and James books. Both formulas, which are identical, call for preparing 3 separate solutions in which A is added to B and AB added to C. James says to let the resultant age a couple of days before use while Crawford is silent on aging before usage. But both say the the solution can be stored for several months as long as it is not exposed to any bright (UV) light. Stevens, on the other hand, calls for 2 solutions that contain the same the same chemicals as Crawford and James but in different amounts (e.g., 10 gm ferric ammonium citrate/100 mL water in a resulting formula volume of 200mL vs 9 gm in a 100mL resulting volume). Stevens also adds A to B immediately before use and says that the resultant AB does not keep for more than a few days.
I am at a point where the coating, exposing and processing steps are mechanical and i can expect consistent results on different days and atmospheric conditions. The next step for me is to play with the formulas to manipulate the coloration obtainable with the process.
Thomas
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