Sorry the amount of Metol in the formula I posted should be 2.5 g
According to this study, D-76H has rather poor keeping qualities, presumably because it's not sustained by the self-replenishing effect of the hq-sulfite reaction.
"Somebody is bound to come by and say the sulfite is not
necessary, and that there are better accelerators. Let me
reply in advance: I get finer grain with sulfite than with any
other method I've tried."
I keep a least chemistry approach in mind. Remember, I'm the
fellow that processes one-shot with one tray. The less chemistry
needed to compound the better. D-76 is loaded with sulfite
while types like FX-1, Beutlers, Rodinal, etc, have very
little but are best for slower already fine grain films.
Lowering the ph leads to finer grain but slower emulsion speeds.
I was using D23, my 8 and 80 gram version, for a while but thought
perhaps I was losing film speed due to low ph. On the assumption
that metol has a not so low turn on ph range I switched to
carbonate. I think my film speed is up some but can't
quantify. I've a fine densitometer but short on time.
I recall having read that there is an optimal sulfite level per unit
volume. I remember, an article by R. Suzuki. Dan
"There are good sulfite-free developers too, and they may
meet your needs. But if you like the look of D-76, I think you
will more likelyprefer a sulfite-based developer. For low-speed
films, this would be less of a consideration."
I mentioned it before, but be careful that what you get at the pharmacy is ascorbic acid. The body also can use dehydroascorbic acid as Vitamin C, but it won't develop film. I think it should be marked on the container, but I don't know for sure if it is required to be identified as anything but Vitamin C.
Some time ago, when I first used phenidone, before I learned about ascorbic acid, I made a substitute for D-23 using 0.1 gram of phenidone + 8 or more grams of hydroquinine along with 100 grams of sodium sulfite per liter. My idea was that the PQ combunation is less sensitive to bromide content than the metol, and the phenidone can only activate a certain amount of hydroquinone, which is usually considered to be about 40 times the weight of the phenidone. My thought was that the developer would be self replenishing. I used to develop a roll and pour the developer back into the bottle. When it got so gross looking that my worry wart started hurting, I mixed a new batch. At the time, I was working full time at NASA, playing in two symphony orchestras and various other musical engagements, taking pictures of guest artists at dress rehearsals and having prints ready for autographing the next day, while trying to be a good father to 6 children. I never had a failure I could attribute to weak developer, and I got 8 or more rolls out of a quart.
I just recently resurrected this formula and it still makes good negatives aout of HP5+. Sulfite IS a good preservative for hydroquinone.
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All about D-76 and many versions at a R. Suzuki site. At Google
Originally Posted by Ronald Moravec
enter, "years of D 76" .
I'll likely give an 80 gram sulfite D-76 a try. My Acculab is
good for .01 gram resolution. A half batch should do for starters.
I've a bunch of amber glass Boston Rounds with Polycone caps;
one serving per bottle. As I use chemistry one-shot, a 1:1 or
so dilution will be needed.
If I read Mr. Suzuki correctly, the borax is needed only IF the
developer is re-bottled after use. Dan
Correction noted and made. Most readings mention the
Originally Posted by Gerald Koch
addition of borax as the cure for the used or oxidized HQ
caused increase in activity. I did read one article which
placed the blame on the hydrolysis of the borax. The
cure? Minus the borax.
I use all chemistry one-shot so never have it used
or oxidized; no used or O2ed, no HQ, no borax. That
leaves 2.5 grams Metol and 100 grams S. Sulfite
which makes for a 1/3 strength D-23.
FX-13 looks interesting. It is a high sulfite, metol, carbonate
brew and, save for the 8 fold increase in sulfite, the same as
FX-1. The results, I'd think, are likely similar to some of the
PC brews mentioned. Likely I'll test a D-76 and FX-13. Dan
Borax is a stable chemical and does not hydrolyse in water. In fact, it is used as a reference to calibrate pH meters; a 0.01M solution (3.814 g/l) has a pH of 9.22 at 20C.
When hydroquinone oxidizes in sulfite solution hydroxide ions are produced which raise the pH of the solution. This causes increased film density and contrast. Various modifications of D-76 have been suggested to get around this problem. The best used a combination of borax and boric acid. One D-76d uses 8 grams of each. Kodak seems to use a smaller amount (perhaps 4 grams each) in their packaged D-76.
"Borax is a stable chemical and does not hydrolyse in water.
In fact, it is used as a reference to calibrate pH meters;
a 0.01M solution (3.814 g/l) has a pH of 9.22 at 20C."
Borax; ph 9.22 at 0.01M. I hope some others see that.
I've always maintained that sodium sulfite is more
alkaline than borax.
"When hydroquinone oxidizes in sulfite solution hydroxide ions
are produced which raise the pH of the solution."
That is only meaningful in the context of when D76 is coming
from; 1927. D76 78 years ago was, I believe, compounded
for large tank and tray processing and intended to be
replenished. For myself, small bottle storage and one
shot use obviate any need for borax. Dan