Effective Film Speed with D76 Variants

[Tom Kershaw]

Thus, there is little logic to it all except for the fact that developer numbers are increasing with time. So, we have HC-110.

PE

Do you know when HC-110 was released? Presumably it has changed over the decades similarly to Tri-X.

Tom

 

[Photo Engineer]

Tom;

IDK when HC-110 was released. I tried searching some data last night for Henn's work and found nothing that would help. I do know that developers evolve hardly at all. Most changes are due to improved manufacturing technology. Thus, Dektol once came sealed in a glass jar with 2 parts. One was in a cardboard container in the jar and the other was in the jar itself. Since they learned to encapsulate ingredients and pack under nitrogen, the whole thing now comes in a pouch as one part, but it is the same Dektol.

The new Tri-x and the old stuff differ vastly due to emulsion technology and EPA restrictions on heavy metals. It has differenc reciprocity, LIK, and raw stock keeping for a few. It is also better in speed and grain.

PE

 

[Ian Grant]

The patent was 1971, in the UK it was mid to late 70's before anyone heard of it.

Ian

 

[Photo Engineer]

Everything you ever wanted to hear about HC-110 but the exact formula.

http://www.covingtoninnovations.com/hc110/

This is courtesy of Bill Troop. He sent his reference on to me.

PE

 

[sanking]

Getting back to D76, I am still trying to figure out how to objectively compare the film speed of D76, standard or any of the variants, with another developer, because , in my experience, they all change in terms of both energy and film speed with age.

Does one assume a freshly mixed D76 for this type of comparison? Or one a week old? Or two weeks old? Or two months old.

Sandy King

 

[Ian Grant]

The problem arises because D76 was designed for replenishment, in practical use most people used to make it up at the end of a working day and season it ready for use the next morning in commercial situation. In practice leave it a day or so and it should be stable enough for 3 weeks to a month.

Michael P. Dosch published research into the variations over time and showed D76 to be relatively stable for a bout 3-5 weeks, but it looks rather though there were errors creeping in from somewhere else in later weeks as in week 13 all his tests densities for D76 & variant atke a simultaneous nos dive only to bounce back two weeks later.

Ian

 

[Photo Engineer]

Getting back to D76, I am still trying to figure out how to objectively compare the film speed of D76, standard or any of the variants, with another developer, because , in my experience, they all change in terms of both energy and film speed with age.

Does one assume a freshly mixed D76 for this type of comparison? Or one a week old? Or two weeks old? Or two months old.

Sandy King

Sandy;

All HQ developers undergo a tiny change during the first few hours after mixing due to the consumption of dissolved oxygen and formation of HQMS (Hydroquinone Monosulfonate). This usually causes an increase and then decrease in activity depending on how much oxygen was entrained during mixing and how the mixed developer was stored.

However, when you test, include a MacBeth checker in the photo of each test for each developer and plot the gray scale on paper for the N, N+ and N- exposures. These curves will give you relative speeds knowing the original densities of the patches on the test chart. All you have to do is match one point on the chart with one print and go from there.

PE

 

[BetterSense]

In practical terms like grain, EFS etc; how does D76h differ from D23? It appears to be nearly the same thing, only with less metol and some borax added. Can it be replenished like D23?

 

[Ian Grant]

D76h has Hydroquinone in it so is very different to D23. You could replenish it but there was no published formula, but it wouldn't be far off the normal D76R with more Borax/Boric acid.

Ian

 

[Lee L]

H76h [sic] has Hydroquinone in it so is very different to D23.

Ian

D76H as published in Anchell and Troop's books is distinguished from other versions of D76 by the lack of Hydroquinone. The reason given is that Haist did this to avoid the increase in activity after initial mixing.

Lee

 

[sanking]

However, when you test, include a MacBeth checker in the photo of each test for each developer and plot the gray scale on paper for the N, N+ and N- exposures. These curves will give you relative speeds knowing the original densities of the patches on the test chart. All you have to do is match one point on the chart with one print and go from there.

PE

Ron,

My way of checking the relative film speed is derived from BTZS testing. In this system five or more sheets of film are exposed with a consistent light source to a transmission step wedge. I use a EG&G Mark VII sensitometer for this. Then the densities of the step wedge are read and entered into a plotting program called Winplotter, which will calculate film speed. It takes a couple of hours to run the tests and plot the results but the results are very reliable.

I always use the same method of development, BTZS type tubes with constant gentle agitaiton in a water bath, and ways develop at the same temperature, 72F.

Sandy

 

[Photo Engineer]

Of course, and that is a better method. The camera method includes lens flare among other things. But, since many people do not have an EG&G or equivalent my suggestion can only be a distant second to yours.

PE

 

[sanking]

Of course, and that is a better method. The camera method includes lens flare among other things. But, since many people do not have an EG&G or equivalent my suggestion can only be a distant second to yours.

PE

Ron,

Many people do BTZS testing with their enlarger. Before I got the EG&G I tested with my Besler 23C enlarger with a Metrolux light integrator. This worked reasonably well but the curve points were not nearly as smooth as with the sensitometer.


Sandy

 

[Ian Grant]

D76H as published in Anchell and Troop's books is distinguished from other versions of D76 by the lack of Hydroquinone. The reason given is that Haist did this to avoid the increase in activity after initial mixing.

Lee

D76h is not D76H they are two different entirely different formulae.

D76h is a Kodak published buffered Borax variation of D76.

D76H is something Grant Haist is purported to have hypothesised in a discussion with Bill Troop (see the FDC).

Unfortunately Bill Troop gave iD76H a Kodak nomenclature something like H76 ie Haist 76 would have been better.

Ian

 

[dancqu]

D76h is not D76H they are two different entirely different formulae.
D76h is a Kodak published buffered Borax variation of D76.

D76H is something Grant Haist is purported to have hypothesised in
a discussion with Bill Troop (see the FDC).

Unfortunately Bill Troop gave iD76H a Kodak nomenclature
something like H76 ie Haist 76 would have been better. Ian

So a D-76 upper case H and a D-76 lower case h. Good
to know. My assessment; Haist's H is nothing more than
a 1/3 strength D-23 and so it is a huge user of sulfite.
With no hydroquinone I don't believe that pinch
of included borax serves any purpose.

D-76 vs D-23. The few posted comparisons I've read
rate the two interchangeable. At the low D-76 ph,
sulfite activated, the hydroquinone acts only to
regenerate the metol. So doing D-76 is a
less expensive D-23. Hydroquinone is
about half the price of metol. Dan

 

[Lee L]

D76h is not D76H they are two different entirely different formulae.

D76h is a Kodak published buffered Borax variation of D76.

D76H is something Grant Haist is purported to have hypothesised in a discussion with Bill Troop (see the FDC).

Unfortunately Bill Troop gave iD76H a Kodak nomenclature something like H76 ie Haist 76 would have been better.

Ian

Ian,

I see that you made the same point a couple of pages back in this thread over the weekend when I wasn't checking APUG. In the interest of completeness, could you post the formula for D-76h (not Haist) here, as few people seem to be aware of it? I've not seen it published anywhere. I have seen a buffered D-76d formula with boric acid.

Lee

 

[Ian Grant]

D76h

D76h

Metol 2.5g
Sodium Sulphite 100g
Hydroquinone 5g
Borax 2g
Boric Acid 15g
Water to 1litre

This is very similar to a (there was a url link here which no longer exists) published in the US & UK, but has the Metol increased to 2.5g

Ian

 

[Lee L]

Thanks Ian.

Lee