Following interests from a few recent threads here, I did a bit of web search for a close analogue of D-76 using ascorbic acid instead of hydroquinone. I found none, because most used phenidone and their base compositions seemed to have adjusted for phenidone. So I did a bit calculation and cut and try. Something to try if you have thought about ascorbic D-76 before the holiday. Metol 2.0g
L-ascorbic acid 5.0g
borax decahydrate 12.0g
sodium sulfite 100g
I used it 1+1 for HP5+ for 11 min at 20C with S.S. tank hand inversion. The neg looks slightly denser than my taste. What I mean is that EKC's packaged D-76 time is a good starting point. Note that this formula uses ascorbic acid, not its sodium salt. That means if you are making this solution for small scale processing or experiment, you can make solution A with all but borax, and B with borax only, and mix 1:1 to make a 1+1 dilution solution. I don't know the keeping property but part A is acidic and should last for a couple of weeks even in a partially filled bottle. You can also play with the amount of part B to mix in. I think 11g to 13g borax per liter is a good range. This developer comes with no marketing hype. I even hesitate to give it a new name so I just added standard EKC suffix for now. Try it if you feel like it and share what you think!

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 13, 2001

Answers

I apologize that the formatting of the previous post is screwed up.

water at 20C to 30C 750ml
L-ascorbic acid 5.0g
metol 5.0g
borax decahydrate 12.0g
sodium sulfite 100g
water to make 1.0 liter

The order shouldn't matter but use regular precaution like dissolving a few grams of sulfite in the water first.

This developer is a bit more active than D-76H (in terms of processing time).

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 13, 2001.

Screwed up again. I never used HTML tags in this forum before... I intended 2.0g of metol as in original D-76. I wish I could erase all and start a clean thread... :-)

I apologize that the formatting of the previous post is screwed up.

water at 20C to 30C 750ml
L-ascorbic acid 5.0g
metol 2.0g
borax decahydrate 12.0g
sodium sulfite 100g
water to make 1.0 liter

The order shouldn't matter but use regular precaution like dissolving a few grams of sulfite in the water first.

This developer is a bit more active than D-76H (in terms of processing time).

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 13, 2001.

The actual image quality has to wait until I print a lot out of the negs, but I'm a bit convinced that ascorbate is actually involved in the image formation in this formula.

I remember HP5+ (and TMX) exhibited brownish tone in XTOL 1+1, and this is also clearly seen with the rolls I processed so far. I also pulled an APX100 neg processed in XTOL 1+1 which was black black. A roll of APX100 processed in D-76Ad 1+1 is also black black. In Microphen, D-76, HC-110, HP5+ were more black than XTOL or D-76Ad. As far as the colors of the negative images are concerned, D-76Ad is closer to XTOL than D-76d. This is presumably a projection of grain structure, many say the finer the grain the warmer the tone, but I'm not sure if it's that simple.

The pH of D-76Ad is higher than D-23/25 type formulae. So low pH is not the case. Sulfite concentration is the same. At this point my best guess is that that vitamin is doing something.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 14, 2001.

> At this point my best guess is that that vitamin is doing something.

That parallels my D-23/ascorbate results. Although the negs didn't go brown (I've seen that frequently with other films) grain was definitely finer even in the initial overdeveloped test film. And it was apparently superadditive with metol.

From discussions hither and yon about Xtol, I gather that the big problems with using ascorbate have been shelf life and keeping the stock solution, but maybe that won't matter too much to us home-brew types.

-- John Hicks (jbh@magicnet.net), December 15, 2001.

Good keeping property is something I like to have in my chemicals, though I don't know about the shelf life of single stock solution preparation of D-76Ad. Before, I asked you whether D-76H exhibits discoloration when it dies. You said you never kept D-76H so you didn't know. Guess what, I know it exhibits brown tint when it's going off.

I kept my XTOL stock solution in PET bottles for months with no visible change in image quality. Some (you) may argue that this is not always the case. We don't really know whether this is EKC's fault or not, though many think so. Gainer's Vitamin C formulae have no sulfite, and it's no surprise they don't keep well. You know, FX-1 doesn't keep well unless you make a 10X or perhaps 20X concentration. Ilfosol-S seems to keep well before dilution. I haven't heared a single complaint about Ilfosol-S yet. Guessing from all these combined I think ascorbate formulae don't necessarily have to sacrifice their shelf life when properly prepared and stored.

Right now, my interest is whether ascorbate version of D-76d and buffered FX-1 really benefit from ascorbate or not. If the answer is affirmative, I'll try to prepare long-lasting stock solution then.

PS. I usually use tap water for photographic use. The tap water in my city is really nice soft water that I have no problems with. Activated charcoal is all I need for my coffee and tea.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 15, 2001.

> You said you never kept D-76H so you didn't know. Guess what, I know it exhibits brown tint when it's going off.

Right; I make small quantities and it doesn't sit around long. I have, however, had a couple of occasions in which apparently it was getting a little weak, just enough to give slight underdevelopment, and I didn't see any tint change.

>I kept my XTOL stock solution in PET bottles for months with no visible change in image quality.

I had good luck with Xtol, which I always decanted into small ready-to-use quantities of stock and stored in the refrigerator, until one of those small containers turned out to be rather dead. What was odd was that the previous day I'd used another container of the same stock and it was fine. Perhaps there was an air leak, I don't know, so I'm not one of those trumpeting "Xtol failure" since it could have been pilot error.

> I haven't heared a single complaint about Ilfosol-S yet. Guessing from all these combined I think ascorbate formulae don't necessarily have to sacrifice their shelf life when properly prepared and stored.

I've seen just a couple of complaints about Ilfosol-S having an unexpectedly short storage life but since no context was given I took them with a huge grain of salt. I've had no trouble myself.

> Right now, my interest is whether ascorbate version of D-76d and buffered FX-1 really benefit from ascorbate or not.

I'm thinking of taking a look at plain D-76 and simply replacing the hydroquinone in the formula with ascorbate and comparing this with my usual D-76H. If storage is a problem it'd be easy to just add the ascorbate to the working solution.

-- John Hicks (jbh@magicnet.net), December 15, 2001.

I also thought about just adding sodium ascorbate for comparison but didn't like the idea; ascorbic acid is a weak acid with Ka of 4.3E-7 and 5.6E-11. I don't know how this affect as a mild buffer, especially when the local oxidation products and sulfite reaction is involved. I don't know if this is significant or not but rather avoid the issue by comparing buffered D-76d against buffered D-76C. It's not perfect but nothing is perfect in photography and still this is fairer comparison, and it is easy to do anyway. Another motivation for me to do this is that with a buffered version, drug addicted HP-5+ doesn't take progressively longer processing time even when diluted. (With HP5+ I want to see smooth gradation and pleasing grain rather than increased accutance, which it inherently has plenty.)

If you have sodium ascorbate at hand but not the acid version, I suppose you could add that to D-76Hd for comparison. If this turns out to be so tiny an issue that doesn't matter, it's good but I don't know that at this moment.

This can also be a problem with carbonate version, as sodium ascorbate and disodium ascorbate would make even more stable buffers at high pH.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 15, 2001.

I tried mixing up some D-76 (ordinary formula), substituting sodium ascorbate for hydroquinone at Anchell & Troop's recommended 1.8x....

It's _really superadditive_. Big-time! The test film was Delta 400; it took at 1:3 dilution at my usual D-76H 1:1 N-2 time to fairly closely match a "normal" CI. Not only that, it's 1/3 stop slower, quite a bit grainier with less fine detail, apparently eaten by the grain.

This variant isn't worth pursuing imho.

-- John Hicks (jbh@magicnet.net), December 17, 2001.

I don't see objectionable grain but I see slight decrease of speed with TMX in D-76Ad 1:1 at 20C. With this stuff I'm happy if I get better result with HP5+. I'm trying something else for TMX anyway.

I don't know where 1.8 came from. Maybe molar weight ratio. The XTOL patent also states that the ratio of ascorbate and superadditive reagent should be pretty high, at least 20:1 if I remember correctly. This is where Gainer's formula is at. But some reported ascorbate is more strongly superadditive with metol than hydroquinone. My ratio is smaller than that, and yours between. I think this parameter may need tweaking.

Your solution is probably around half a pH unit higher than XTOL, at least before you soak film in it. I don't exactly know how XTOL achieves finer grain than D-76 with several films, but many think lower pH gives one reason. XTOL patent specifically prefers a suitably formulated borate buffer solution. We kinda know what it is. So pH is one thing I am tweaking now.

Buffered low pH and the property that dilute solution pushes better is kinda common with Microphen. So I'm suspecting some of XTOL's marketed advantage came from buffered low pH to which ascorbate adds something. Microphen or ID-68 might have been a better starting point for this project, I might think, though I use metol.

There has been a criticism about adding sulfite to Rodinal as a panacea because all it does may be just lower the pH profile a bit or regenerates reductants in a different way, or something totally different from solvent effect. Ascorbate might also be the case at least in part when added to Rodinal-type developer. Gainer's common salt experiment is interesting, but I wonder if it works equally well on fast films and T-grains, which may give some clue in further speculation.

Gainer's formula also contains less reductants and more base. I don't know if this is a result of image quality tuning or his cost calculation (probably both) but I think D-76Ad 1+3 or 1+4 for T-MAX and Delta may suggest something.

Just an ascii text dump of what I am thinking about. Either way, I know formulating a developer isn't that easy like make one up and it works great. Just as hard as making a really great blend of coffee :-)

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 17, 2001.

Someone should really try this: 3 g. metol or 0.3 g. phenidone 2o g. l-ascorbic acid (Vitamin C) water to 500 ml This is solution A. For B, use any thing you like, but first try either 10% Kodalk or sodium metaborate.4H20 or 60 g. borax + 14.5 g. sodium hydroxide per liter and use 50 ml of A and 100 ml of B. The A solution keeps well. The problem with XTOL and ascorbates with phenidone in general is not that they don't keep well but that you do not have the usual warning color change when they have overstayed their leave.

-- Patrick A. Gainer (pgainer@rtol.net), December 18, 2001.

I should have mentioned that if you want a longer lasting split stock storage method for your D-76AD, put the developing agents, including ascorbic acid, not the ascorbate, in one solution and everything else in the other.

-- Patrick A. Gainer (pgainer@rtol.net), December 18, 2001.

I am using Gainer formula but haven't done any real test to comment on. It's really easy to make an usable formula based on some simple calculation and cut and try, but it's much harder to seriously test and eveluate the developer's performance with each film I use.

Regarding the stock solution, I put sulfite together with developing agents, not with the base. Even if I keep metol/phenidone solution acidic, without sufficient sulfite, it seems much quicker to die. I remember metol/hydroquinone/boric acid/metabisulfite solution died hopelessly quickly even though the bottle was totally filled with the solution. Same with phenidone. For this reason I would not keep Gainer developer without sulfite, and mix fresh each time as he recommends.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), December 19, 2001.

I kept phenidone and ascorbic acid together for over a month in a partly filled plastic bottle and it was good to the last drop.

-- Patrick A. Gainer (pgainer@rtol.net), December 19, 2001.

It's threads like this one that separate this forum from the "equipment discussion" forums. This is great!

I don't have much to add except on Ilfosol-S shelf life. I tried it a couple of years ago and apparently bought a new bottle that was nearly dead. I don't know how long the developer had been on the shelf, but even with increased time and temperature, it was unable to develop films beyond a severely underexposed look.

-- Brian Hinther (brianh@onewest.net), December 29, 2001.