Consider the 1l packs and tins and you'll notice that the net weight isn't always the same. I've seen 132 and 135g. Now, consider the 1US gal packs and divide their net weight (482g) by 3,8. This gives you ~127g. That's enough of a headache. It seems that the Microdol-X formula wasn't always the same. Some tweaks have probably been made, maybe because a chelating agent was substituted with another. But in any case, the substitute formula lists 100g sulfite, 5g Metol and 30g sodium chloride, for a total of 135g. Not too far away eh?
While it is true that metol, SS and good old pickling salt will do the trick just as well, my interest was in what made Microdol-X impart a brownish tone to my negatives. I've wasted more time on a bar stool and got nothing in return but a headache and an empty wallet. This waste of time really cost me nothing. JohnW
I don't think so. I have used the homebrew version with several films and TMax 100 in particular got a brownish tone, especially noticeable in mid to high densities. The exposed leader has a definite brown tone, so much so that seeing this alone could fool someone in believing that it was developed in something like Pyrocat. I also have a suspicion that this brown tone is lessened with overdevelopment, something that would make sense IMHO.
I agree that some ideas of this patent may have been used later by the same inventors, but not in Microdol. However, what is your objection to their Example 5 being Microdol?
Well, for whatever it is worth, I just finished a little experiment with a metol-based concoction and Kentmere 100. The concoction was the following (per liter): metol 8 g, sodium sulfite 2 g, sodium citrate 44 g. NO chloride. I added citrate until the pH of this concoction was 7. I then left it for a month in a tightly closed vessel with very little air, to see how fast it would display any sign of oxidation. As there was none, I developed a few clips to determine the time. It turned out to be 70 minutes (yes, seventy) at 20 degrees Celsius. I only agitated it once every 10 minutes. However, I was rewarded with a soft negative that was very fine grained. I would not bet (without a microscope) that it was better than in the "Microdol homebrew", but it confirms my idea that at least for this film and metol the low pH is the essential factor for fine grain. Obviously, I went a little too far with the pH, and maintaining it in the narrow range between 7.7 and 7.9 is a compromise between development speed being within practical limits and fineness of grain, as produced by metol. This little experiment also provides an indirect hint as to why some people like D-23 and some don't, as depending on the purity of sulfite they may actually have different developers in their hands. Likewise, since a lay person has no means of adjusting pH with this level of precision, it means your outcome may vary also with the "homebrew Microdol" depending on the actual quality of chemicals used. Trying to use it with replenishment is asking for further trouble and may eventually completely defeat the purpose. It may "work" but there are definitely better developers out there.
Yes, sort of. In my perception D-25 was constructed to lower the pH of D-23, which action in itself results in a finer grain, with a lot of sulfite acting as a buffer and a halide solvent. To isolate the effect of low pH, I did make another buffer, titrating metol with sodium citrate, but lowered sulfite to a minimum. At this point I am not going to try this concoction on all films currently on the market.
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