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  #1  
Old 8th March 2019, 09:37 AM
JakubV JakubV is offline
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Default D-76 h

Metol...........................2,5g
Sodium sulfite (anh.).....100g
Borax (decah.)..............2g
Water..........................1l
(by Grant Haist; published by Anchell&Troop)

Should not increase activity with storage compared to D-76 (incidentally has rather short shelf life).
However, sources differ in developing times - recomended starting points are same as for D-76, but there are reports of considerably reduced densities.
Since the PH is exactly the same, with reduced amount of developer and no superadditivity, I'd indeed expect longer times. The question is, how much - looking at some developing curves, 30-40% increase seems reasonable. Do you have some experinences with this developer?
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  #2  
Old 8th March 2019, 10:02 AM
Lostlabours Lostlabours is offline
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That's not the formula for D76h, that's a hypothetical formula that Haist came up with in a discussion with Troop. It's loosely based on the Eastman Kodak Research original Fine Grain developer published before D76..

The official Kodak D76h formula contains Hydroquinone

Metol...........................2,5g
Sodium sulphite (anh.).....100g
Hydroquinone................5g
Borax ..........................2g
Boric Acid.....................15g
Water..........................1litre

Kodak publish quite a few variations of D76 in the 1930's Grant Haist would have been aware of the original EK Research fine grain developer, Troop wasn't

Ian
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Old 8th March 2019, 11:00 AM
JakubV JakubV is offline
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Thanks for the correction Ian. Official one seems similar to D-76D (0,5g less metol, 8g of borax and 8g of boric acid).
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Old 8th March 2019, 01:34 PM
Lostlabours Lostlabours is offline
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Here's a list of some of the D76 variants and similar developers like the Ilford PQ version Autophen.

Ian
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Old 15th May 2019, 05:22 PM
Svend Svend is offline
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A couple of questions on this, if I may...

- Does the increased activity of D-76 over longer storage time only happen to, say, half-full bottles; i.e. where there is some air in the bottle? Or does it affect full bottles also?

- Can one expect any image quality differences between D-76 and D-76H?

Thanks!
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Last edited by Svend; 15th May 2019 at 05:26 PM.
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Old 24th May 2019, 08:51 AM
JakubV JakubV is offline
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Hi Svend, reports say increased pH as result of hydroquinone oxidation...so, full bottle shouldn't change pH, I'd guess (only if was more interested in chemistry at school , can HQ react with oxygen form water?).
Some people swear that metol only developers give better edge sharpness than metol+HQ - as for my experiences, D-23 1+1 is very sharp, but I doubt that there is some difference compared to D-76 (at least up to 30x40 print from 35mm).
Also, without superadditivity, metol only developer should build high density areas slower, providing less contrast (I have noticed and use this with D-23).

Last edited by JakubV; 24th May 2019 at 08:55 AM.
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Old 24th May 2019, 12:47 PM
Svend Svend is offline
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Quote:
Originally Posted by JakubV View Post
Hi Svend, reports say increased pH as result of hydroquinone oxidation...so, full bottle shouldn't change pH, I'd guess (only if was more interested in chemistry at school , can HQ react with oxygen form water?).
Some people swear that metol only developers give better edge sharpness than metol+HQ - as for my experiences, D-23 1+1 is very sharp, but I doubt that there is some difference compared to D-76 (at least up to 30x40 print from 35mm).
Also, without superadditivity, metol only developer should build high density areas slower, providing less contrast (I have noticed and use this with D-23).
Ah, so that's what's at work here. I did some searching before I posted my question, but could not find what was actually causing of the activity increase. Thanks for finding that.

BTW, I've started storing D76 stock solution in 500ml bottles, so the whole bottle is used up in a single session. So no more storage in half-full bottles.

I agree re. metol-only formulas. I use Perceptol a lot, esp. for scenes where there is a lot of contrast (snow, full summer sun, etc.) and find it to be terrific stuff. Very sharp, less contrast, a little softer rendering than D76, but still great depth of tones. Never tried D23, but I hear it is also excellent. Probably quite similar to Perceptol, I would guess.
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Old 3rd December 2021, 09:18 PM
Stocky Stocky is offline
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Quote:
Originally Posted by Lostlabours View Post
That's not the formula for D76h, that's a hypothetical formula that Haist came up with in a discussion with Troop. It's loosely based on the Eastman Kodak Research original Fine Grain developer published before D76..

The official Kodak D76h formula contains Hydroquinone

Metol...........................2,5g
Sodium sulphite (anh.).....100g
Hydroquinone................5g
Borax ..........................2g
Boric Acid.....................15g
Water..........................1litre

Kodak publish quite a few variations of D76 in the 1930's Grant Haist would have been aware of the original EK Research fine grain developer, Troop wasn't

Ian
I noticed on Ian Grant's web site several Kodak variants with only a little borax and quite a lot of boric acid, including this one (above). I wondered why the pH wouldn't be too low for normal development. Were these for a particular purpose?
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Old 4th December 2021, 09:10 AM
Lostlabours Lostlabours is offline
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Quote:
Originally Posted by Stocky View Post
I noticed on Ian Grant's web site several Kodak variants with only a little borax and quite a lot of boric acid, including this one (above). I wondered why the pH wouldn't be too low for normal development. Were these for a particular purpose?
The lower pH slows development and that helps produce finer grain, it has to be remembered that at 100g per litre the Sodium Sulphite acys as a mild Silver solvent but some of that Silver re-plates onto developed Silver particles.

Ian
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  #10  
Old 4th December 2021, 05:40 PM
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Uwe Pilz Uwe Pilz is online now
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Please keep in mind: The first Formula is a metol only developer without redox system (usual HQ). Ths developer has a very short shelf life, less than a week. You are always in danger getting thin negatives. Beside this, metol only devs los around one stop.
From my point of view, this are specialized developers which should only used for fine grained film lik PanF+. There are said producing a slightly finer grain. Because the lose a stop it is normally easier using a slower film. But if you still use the film with the lowest ISO it's usage may make sense.
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