D76 and it's Variants

[NortheastPhotographic]

With XTol being somewhat unreliable these days, (My whole stock has been recalled) I am using D76 a bit more.

I'm curious about D76H which omits the HQ for slightly more metol. If this is a simpler formula that delivers the same results, with less instability, why did Kodak not adopt it as their standard version?

There must be some good reason to stick with the original formula...

 

[Kino]

Wasn't Grant Haist the one who devised D76H at a much later date?

Maybe it was already well established and Kodak didn't want to fool with the formula and infuriate devoted users?

 

[BradS]

Hydroquinone is considerably less expensive than Metol ?

actually probably not that but almost cerrtainly something to do with the total cost of making such a change.

 

[Adrian Bacon]

With XTol being somewhat unreliable these days, (My whole stock has been recalled) I am using D76 a bit more.

I'm curious about D76H which omits the HQ for slightly more metol. If this is a simpler formula that delivers the same results, with less instability, why did Kodak not adopt it as their standard version?

There must be some good reason to stick with the original formula...

I'm in the same boat. I've reached out to Robert's Distributors about switching over to Ilfotec DD. It seems pretty straight-forward to do and has a replenishment rate of 50ml per 135-36 instead of the usual 70ml. It does cost more, but would otherwise be a near drop in replacement from a workflow perspective. Obviously there would be different processing times than XTOL, but they have a data sheet that lists starting points for a whole pile of films, so at least you can use that until you work out your own times for whatever your standard contrast is if their listed times don't give you what you want.

 

[Ian Grant]

Wasn't Grant Haist the one who devised D76H at a much later date?

Maybe it was already well established and Kodak didn't want to fool with the formula and infuriate devoted users?

The original Eastman Kodak Research Fine Grain Developer published before D76 is similar but with no Hydroquinone also used slightlu=y more dilute. Haist was most likely alluding to this developer when suggestiong removing the Hydroquinone

D76h is a Kodak variant of D76 and contains the usual 5g Hydroquinone and 2.5g Metol and an addition of 15g Boric acid alongside the 3g Borax.

Ian

 

[Tom Kershaw]

Ian Grant has published a useful collection of formulae here: http://lostlabours.co.uk/photography/formulae/formulae.htm

Ah, I see Ian has replied at the same time.

 

[Ian Grant]

How do we know they did? D76 is just a product name at this point, as far as I'm aware. The recipe is not on printed on the bag. I have a deep suspicion that "D76" these days simply describes a "class" of developers. I have been regularly using three: ID-11, Arista 76 and Ultrafine D76. They are definitely not the same. The one from Ultrafine is absolutely amazing, somehow it makes grain more "packed" that the other two.

Kodak increaseded the buffering in D76 some yearsago, this was most likely done at the time amateurs began using it dilute at 1+1 and 1+3 to keep the pH stable. The indications are that they increased the Borax to 4g and added 2g Boric Acid.

Ian

 

[Tom Kershaw]

Kodak increaseded the buffering in D76 some yearsago, this was most likely done at the time amateurs began using it dilute at 1+1 and 1+3 to keep the pH stable. The indications are that they increased the Borax to 4g and added 2g Boric Acid.

Slightly off topic but I've been using the Adox MQ Borax formula recently to process a few rolls of Delta 400 35mm film with good results, solutions diluted 1+1 or 125ml dev + 125ml water per film. I'm given to understand that some sources recommend a minimum of 250ml (undiluted) per film. Do you have a view on minimum quantities for these developers?

 

[Ian Grant]

Slightly off topic but I've been using the Adox MQ Borax formula recently to process a few rolls of Delta 400 35mm film with good results, solutions diluted 1+1 or 125ml dev + 125ml water per film. I'm given to understand that some sources recommend a minimum of 250ml (undiluted) per film. Do you have a view on minimum quantities for these developers?

I always used Adox Borax MQ replenished as I found it more effecicient. The Kodak and Ilford figures err on the side of being overly cautious and make 1+1 dilution an expensive option, ultimately it's what works that matters. I think when I used ID-11 at 1+2 at someone elses request to process his films I used 100ml of stock plus 200ml water, the results were superb.

Ian

 

[RalphLambrecht]

With XTol being somewhat unreliable these days, (My whole stock has been recalled) I am using D76 a bit more.

I'm curious about D76H which omits the HQ for slightly more metol. If this is a simpler formula that delivers the same results, with less instability, why did Kodak not adopt it as their standard version?

There must be some good reason to stick with the original formula...

D76H is a perfect formulation for me and I use it ever since I tried it or the first time.In my setting it is stable for at least two years.

 

[relistan]

I’ve not used that variant but I have used two divided D-76 variants: Vestal’s version as formulated by Anchell and Troop, and the packaged product from Photographers Formulary. Both were fine and delivered somewhat flat negatives as you would expect. In high contrast scenes the Vestal version was good. I had to extend the times in the first bath to get good negative density.

 

[mshchem]

With XTol being somewhat unreliable these days, (My whole stock has been recalled) I am using D76 a bit more.

I'm curious about D76H which omits the HQ for slightly more metol. If this is a simpler formula that delivers the same results, with less instability, why did Kodak not adopt it as their standard version?

There must be some good reason to stick with the original formula...

Well when these formulae were developed, EK Research was developing cutting edge technology. Puns intended
The answer is Superadditivity.

https://en.wikipedia.org/wiki/Superadditive_developer

Mechanism (source Wikipedia )
There were several historical theories about the mechanism of superadditive development, until G. I. P. Levenson elucidated the regeneration mechanism. It is useful to review modern treatment of the development mechanism described as an electrode process.

Of the two developing agents that are superadditive, the following is usually the case:

1. Agent 1 has lower reduction potential but much higher adsorption to the silver halide crystals.
2. Agent 2 has higher reduction potential but much poorer adsorption to the silver halide crystals.

Agent 1 is the developer that reduces the silver halide crystals. Oxidation product of Agent 1 is reduced back to the original form by Agent 2. In other words, the ultimate source of the electrons used to develop image comes from Agent 2. For this reason, in modern convention, Agent 1 is usually called electron transferring agent or ETA. Agent 2 is usually called the main developing agent.

As obvious from the above mechanism, developing agent with very stable semiquinone radical form (the first oxidized form of the ETA) tends to make more superadditive combination. Also obvious from the above mechanism is that Agent 1 has to have an intermediate reduction potential in the developer solution between the Fermi energy level of silver (the developing image silver) and the reduction potential of Agent 2 in the developer solution.

Examples of Agent 1 include: Phenidone, Dimezone S, Metol, p-aminophenol, glycin, Eikonogen. These agents have nitrogen atoms that give strong affinity to silver halide (argentophilic) as well as hydrophobic end, effectively acting as a surfactant between the developer solution and silver halide crystals.

Examples of Agent 2 include: hydroquinone and ascorbic acid. These agents have stronger reduction potentials than those of Agent 1 group, but they have very poor adsorption on silver halide crystals, due to lack of argentophilic end.

However, there are many developer combinations that exhibit superadditive development.

 

[doctorpepe]

Here is an interesting D-76 "variant" I had never seen before, found in Glafkides' Photographic Chemistry, Vol 1, p 76. Haven't ever tried it.

 

[Pixophrenic]

See post #11 in the discussion about this developer that was first posted by Ian Grant in the Resource section in 2013. Oddly, this developer a.k.a. Smethurst developer, is mentioned in several books throughout the 20th century, but none of the authors apparently tried it.