In my experience, the new Kodak bags do not store Microdol-X very well, I have had several go bellyup. (Dark crystal formations that mix into a dark solution that I wouldn't dip film into). On the other hand I have some Microdol-X in cans that of course are much older, and they have all mixed up well, and I have only one left!
As to the Microdol-X formula, I have'nt seen it anywhere, I have only seen formulas that are supposed to be like Microdol-X but don't seem to be anything like them. Microdol-X has sodium chloride in it.
And while Microdol-X may only be D-23 with sodium chloride and some mysterious sequestering compound, how much NaCl and what sequestering agent?
I've only been using it for 40 years or so.
30 grams of sodium chloride sounds about right.
A fine grain Metol Sulfite developing solution containing common salt was proposed by Edgar Hyman. This formula was published on page 379 of the Fine Grain Developers Chapter in Volume I of Modern Photographic Processing (Grant Haist, 1979, John Wiley and Sons, New York).
In this same chapter, Haist also discusses Kodak D-76 (Capstaff 1926) and some of its Kodak variants and also discusses Kodak D-23 (Henn and Crabtree 1944) and Kodak D-25 (D-23 plus sodium metabisulfite).
Hyman’s Fine Grain Formula (1964):
Metol...................................5 grams
Sodium Sulfite, anhydrous...............100 grams
Common Salt (Sodium Chloride) ...........30 grams
Water to make............................1 liter
Less salt was said to give more grain but higher film speed. A modification for one-time use was also suggested. The developing solution is diluted with an equal amount of water. “Tri-X rated at 400 ASA was developed for 11 minutes at 68°F and said to give “finer grain than D-76.”
Additional discussion of the effects of sodium chloride on silver bromide and silver bromoiodide crystals can be found on pages 378 and 379 of Haist’s book together with this developer formula:
G.F. Van Veelen and W. Peelaers Low pH Metol/Sulfite Developer (1967)
Metol...................................2 grams
Sodium Sulfite, anhydrous...............2 grams
Sodium Chloride ........................2 grams or 100 grams
Sodium Diphosphate ....................10 grams
Water to make..........................1 liter
pH 7.0 or 8.5
Van Veelen and Peelaers observed that compact silver particles with a brownish tone were formed by this developer. They hypothesized that solution physical development was taking place.
I have not tried either of these developers.