D72 stock more concentrated

ericdan · Sep 8, 2020

I am switching from MCC110 and Neutol WA to fomabrom and D72. Didn’t like Neutol WA with fomabrom.
I have all the chemical ingredients. I usually make up a liter of working solution and once in a while dump half and refresh it with new working solution mixed from concentrate. That worked well with my Neutol concentrate. For D72 I don’t want to mix up an entire liter of stock solution because it’s not that concentrated. Would the chemicals dilute in less water? Let’s say 500ml instead of a 1000ml?

thabks?

voceumana · Sep 8, 2020

D-72 (and Dektol) are normally used in a 1:2 dilution for a working solution; i.e., you use 1 part stock soliution and add 2 parts water. Working solution is normally used just once. Back in high school, I make up the developer as a working solution (i.e., I mixed a 1 quart package in 3 quarts of water), and kept it in full bottles, even reusing the solution. But I didn't mix unused developer with re-used developer. It seemed to work fine. You can always try that approach.

Rudeofus · Sep 9, 2020

From "Role of Phenidone in Modern Processing" by L. A. Mason in "The Journal of Photographic Science", vol 13, p 205ff:

The lower concentration of Phenidone enables much more concentrated developing solutions to be prepared than is the case with metol developers. Both Phenidone and metol form 1:1 molar adducts with hydroquinone, and in concentrated solutions it is these complexes which tend to crystallize out first, this tendency being greater at the lower alkalinities. With MQ developers this crystallization becomes a serious problem if the preparation of liquid developer concentrates is attempted. With Phenidone, liquid developer concentrates can be prepared which require high dilutions to prepare working strength developers.

Unless you are heavily invested in Metol, I recommend you change to Dimezone-S (traditional Phenidone hydrolyzes over time). There is some chance, that you can dissolve the chems for 1000ml D-72 in just 500ml, but there could be trouble later on when aerial Carbon Dioxide has lowered the pH of your developer.

Ian Grant · Sep 9, 2020

I mix Ilford ID-78 which is the warm-tone version of ID-62 essentially the difference is ID-78 has no Benzotriazole and a little extra Bromide, ID-62 has less Bromide but Benzotriazole to ensure Neutral tones. ID-78 was sold as a powder developer it's successor is Harman Warmtone developer but is really just a Liquid concentrate version of the same developer.

If you substitute Potassium Carbonate and a little Sodium Hydroxide for the Sodium Carbonate you can mix a concentrated version of ID-62 or ID-78. Liquid Dektol is a similar PQ developer using Dimezone rather than Phenidone. You can mix concentrated MQ developers because the Metol would oxidise too rapidly. ID-62 is the PQ version of Ilford's older MQ developer ID-20.

Rudeofus said:
Unless you are heavily invested in Metol, I recommend you change to Dimezone-S (traditional Phenidone hydrolyzes over time). .

My experience is that Phenidone based developers have a better shelf life than Dimezone-S. It seems largely Kodak marketing and disinformation that Phenidone has poor keeping properties, I have some 1961 Ilford Phenidone that's as good as fresh Phenidone bought last year. It's odd that British books state Phenidone keeps well and US the opposite.

Ian

Tom Kershaw · Sep 9, 2020

I posted this before, but when I did a range of tests several years ago now, I found the D-72 produced the strongest results in terms of achieving a colder tone. Recently however I have mostly used ID-78 as it works well with many papers. D-72 is a good match with ILFOBROM GALERIE so may also work well with the Foma graded papers although I've not tried them.

Donald Qualls · Sep 9, 2020

ericdan said:
For D72 I don’t want to mix up an entire liter of stock solution because it’s not that concentrated. Would the chemicals dilute in less water? Let’s say 500ml instead of a 1000ml?

I have mixed (outdated when I mixed it) commercial Dektol in half the water -- because it was a 5 gallon package, and I had limited storage containers -- and kept the stock solution (in sealed glass jars with butane blanketing) for about fifteen years. I recently used some of the 2x strength stock, diluted 1+19 (= 1+9 strength from standard stock) for film and it worked fine. So my answer would be, "Yes, it not only works, it works very well, and keeps much better than standard stock as well."

Rudeofus · Sep 9, 2020

Ian Grant said:
You can mix concentrated MQ developers because the Metol would oxidise too rapidly.

There are concentrated MQ developers, e.g. Kalogen. This developer lasts for several months. It avoids the MQ precipitation problem by working at very high pH.

Ian Grant said:
My experience is that Phenidone based developers have a better shelf life than Dimezone-S. It seems largely Kodak marketing and disinformation that Phenidone has poor keeping properties, I have some 1961 Ilford Phenidone that's as good as fresh Phenidone bought last year. It's odd that British books state Phenidone keeps well and US the opposite.

Dimezone-S is quite a bit more expensive than Phenidone, yet Ilford uses Phenidone B and Dimezone-S across their liquid product line. Phenidone might last longer in powder form (Microphen contains Phenidone), but people often prefer liquid developer concentrates, and once dissolved in water Phenidone hydrolyses. If this is all evil Kodak propaganda, then Ilford and Tetenal must have sadly fallen for it.

Ian Grant · Sep 9, 2020

I think in bulk Dimezone-S is significantly cheaper than Phenidone, the switch was made when Ilford sub-contracted chemistry manufacture to Champion, Ron Mowrey (PE) mentioned the price difference some time ago.

Champion was formed from the gradual merging of various other companies including May & Baker a British manufacturer of raw photo and agricultural chemicals, and also sold developers etc in bulk and for amateur use. Champion still use the old May and Baker trade names Mydoneg and Mydoprint.

My experience is that Phenidone based concentrated developers commercial and home made have (or had) a slightly better shelf life than commercial Dimezone based versions and that seems to be the experience of others as well. With Pyrocat HD I've found no noticeable drop in activity of Part A which contains Phenidone a fter 3 to 4 years, that's mixed in de-ionised water not Glycol, but then that's in an acidic solution, the moment that last of the Metabisulphite breaks down the Pyrocatechin oxidises rapidly.

Ian

subsole · Sep 9, 2020

ADOX Adotol is my favorite developer with Fomabrom : https://www.fotoimpex.com/chemistry...oper-powder-to-make-1-l.html?cache=1599669769

iakustov · Sep 13, 2020

I always prepare D72 1+2 fresh from powder chemicals right before use now, because when I kept stock filled in brown glass bottles it always got dark in about a month time since it was made. Is it due to a bad methol quality?

Rudeofus · Sep 13, 2020

Ian Grant said:
I think in bulk Dimezone-S is significantly cheaper than Phenidone, the switch was made when Ilford sub-contracted chemistry manufacture to Champion, Ron Mowrey (PE) mentioned the price difference some time ago.

This is strange, because I can get Phenidone much cheaper and much easier than Dimezone-S. Many suppliers of photochemistry carry only Phenidone. Maybe things are different in larger quantities.

Ian Grant said:
My experience is that Phenidone based concentrated developers commercial and home made have (or had) a slightly better shelf life than commercial Dimezone based versions and that seems to be the experience of others as well. With Pyrocat HD I've found no noticeable drop in activity of Part A which contains Phenidone a fter 3 to 4 years, that's mixed in de-ionised water not Glycol, but then that's in an acidic solution, the moment that last of the Metabisulphite breaks down the Pyrocatechin oxidises rapidly.

Pyrocat HD (and its variants are no good example. Phenidone hydrolyzation happens in alkaline solution, while Pyrocat HD keeps the Phenidone slightly acidic. Whoever formulated it probably had very good reasons to mix it in two components. I am not aware of any Phenidone based single liquid concentrate developer.

D72 stock more concentrated

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