D-76 shadow detail

Michael R 1974 said:

That is all true, of course - but is most true when looking at one specific characteristic of a developer (speed for example), and less true when looking at the speed-grain-sharpness relationship. While it is always the combination of components which must be analyzed, depending on the desired characteristics, certain combinations of components (including developing agents) are more ideally suited than others. Generalizations are always problematic - especially considering the film is a very important variable, but some broad characterizations can be made.

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and fog level, ... Life,... Cost,... eg if you are only going to use it 1+1 then adding KBr to stock may be desirable?

Way back when Kodak did say D-76 had unsurpassed shadow detail. It had competition from several similar developers from others, but D-76 really was king because of the Kodak marketing clout. Now Kodak says Xtol is a bit better, but D-76 is still way up there. Why? It isn't any one thing but the whole package. The ingredients make a very well balanced developer that gives excellent, enhanced film speed, fine grain, and excellent shadow detail. Of course, you will never notice its shadow detail advantages unless you expose your film very accurately, but D-76 is also tolerant about exposure. All these things plus simple formulation are why it has been so popular for almost 90 years.

OK, I worked hard within the past 24 hours in order to prove my point. 'My point' is really an attempt to remove some misconceptions about metol/HQ ratios. They are not all that important and, yes, 'universal' developers (optimized to develop prints in their respective formulations) are just as good for film. Yes, they really are, including Dektol.

Dektol's 'bad aspect' is its reduced life in an open tray, compared with D-76. However, when stored properly (glass or PET plastic with no air space), Dektol will last indefinitely, just like D-76 will.

I photographed an old (damaged, but subsequently repaired) Hummel. The full portrait is from the D-76 negative. The 20x enlargements are (indicated) from separate negatives developed either in D-76 (1+1) or Dektol (1+19). There is no apparent difference between the two. No, Dektol does NOT lead to more grain. The misconception is due to the fact that when diluted far less, it becomes extremely difficult to develop to only a normal extent. Overdevelopment with any developer (made much easier to do with Dektol) will lead to more pronounced grain. The increased alkalinity of D-72 (Dektol) does NOT lend itself to more grain. If I had used Dektol full strength but was able to accurately develop my negative to the proper gamma (probably after 30 seconds!) the grain would be the SAME.

Again, Dektol can be readily used as a normal negative developer. The economy is rather profound with a one liter size making 20L of working solution, handily developing at least 80 36-exp rolls of film.

My Dektol dilution is not cut in stone, but merely done to approximate normal development times. I use ambient temps (in my case 80F) so dilute more or less as your desired times indicate. There is no inherent difference with grain, acutance, or contrast. (My contrasts/ densities might be slightly off due to slight deviations in development times. If the D-76 neg actually looks a tiny bit grainier, it is because it was developed a bit more than it should have been. ) As importantly, there is absolutely no difference in shadow threshold: both negatives show equal exposure, about EI 25.

The film used was 35mm Pan F+ (rebadged by Freestyle as Arista 50, bought ten years ago.) - David Lyga

All I can say, Michael, is that the negatives are consistent with shadow detail. Electronic imaging and, as I said, the very slight overdevelopment of the D-76 negaitve, leads to this slight difference. - David Lyga

Gosh. Around and around we go, as usual. ... "Beck thar in 1943 on paige 254 parygarph foourteen of Kodayk dooz-it-yerself, Mz Maud Laudberry done sez". Gosh, get a dang densitometer, do your thing, and measure the result with modern film. I already know the result; but
I should say exactly the opposite of what I know to be the case, and that way Michael will inadvertently agree with it! Therefore I will say
nothing. That will confuse him.

DREW WILEY said:

Gosh. Around and around we go, as usual. ... "Beck thar in 1943 on paige 254 parygarph foourteen of Kodayk dooz-it-yerself, Mz Maud Laudberry done sez". Gosh, get a dang densitometer, do your thing, and measure the result with modern film. I already know the result; but
I should say exactly the opposite of what I know to be the case, and that way Michael will inadvertently agree with it! Therefore I will say
nothing. That will confuse him.

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Please eat an apple.
And 40 Hail Marys...

If I had a penny for every damn sheet of film I've densitometer-plotted with either D76 or HC-110 I could probably go have lunch at the most
expensive restaurant in town right now. So 'scuse me while the rest of you theorize, hypothesize, and otherwise chew the cud!

David Lyga,

I think your tests are fine.

I think they show there is little difference between D-76 1:1 and Dektol 1:19. They are both Metol-Hydroquinone developers and the difference is in their alkaline component - Dektol (D-72) uses "carbonate" which might otherwise increase grain, but you dilute it so maybe that's why you don't get graininess.

My tests with Dektol 1:9 didn't give me "golf ball sized grain." I never figured out how to get that. I got more "graininess" in my experiment due to the fact that I chose a half-frame camera... a trick that "works" better than trying different developers.

My preference, would be to stick with D-76 1:1. Of your pair, I "like" the D-76 better... Though I don't think I can quantify the difference.

Thanks.

DREW WILEY said:

Gosh. Around and around we go, as usual. ... "Beck thar in 1943 on paige 254 parygarph foourteen of Kodayk dooz-it-yerself, Mz Maud Laudberry done sez". Gosh, get a dang densitometer, do your thing, and measure the result with modern film. I already know the result;

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Drew,
Densitometer results with various developers are already available, see the section near the end Judge Holm test:
http://www.covingtoninnovations.com/hc110/
Unfortunately they are not of any use to answer the original question related to how the compounds in the developer cause differences in curves.

To understand the dependencies you would need to be an organic chemistry major?
The super additivity of the MQ pair its dependency on ratio, sulphite concentration and pH etc.,
The buffer pair holding the pH constant (in D76d).
And the changes in ID68 that ilford did for the (maybe) 1/3 stop gain of Microphen.

Anyone to explain?

Not all combinations of developing agents are super-additive. The Kendall-Peltz Rule describes what must be present for an organic molecule to be a developing agent.

A - (C = Z)n - A'

A and A' must be either hydroxyl groups, -OH or amine groups, -NH2, -NHR, or NRR' where R is a substitutuon group like methyl or ethyl ... Z is either a carbon or nitrogen atom. n is a small interger like 1, 2, or 3. The backbone of the molecule must consist of alternating single and double bonds as indicated in the formula.

For a developing agent pair to be super-additive one agent must have both A and A' be hydroxyl groups. For the other member A or A' must be a hydroxyl group and the other group must be an amine group, -NH2, -NHR, NRR'.

In D-76 there are two developing agents, metol and hydroquinone. This is a super-additive pair. The hydroquinone fits A and A' both being hydroxyl groups and metol fits by having one hydroxyl group and one amine group, -NHR where R is -CH3.

There is an optimum ratio between the two developing agents where developing activity is at a maximum. For an MQ developer this ratio is M:Q = 28:72 weight for weight. For a PQ developer this ratio is P:Q = 7:93. These ratios are seldom used exactly as there are other considers for a developer such as contrast, granularity, and emulsion speed.

very educational;thanks for posting

Thanks Alan, but I've already done far more extensive plotting and testing relative to my own applications. Since a lot of this has to do with
use of black and white film in very precise color printing lab applications (color separations, masking), going into details is just going to cause the usual commotion for people who do not use film in this manner. But my premise is the practical CUMULATIVE result. There might be a lot of academic emphasis here in merely the chemical aspect - and that is indeed interesting in its own right - but I personally like to emphasize how certain other factors have a bigger footprint in terms of detail resolution on the toe. Now I will admit that I mainly work
with sheet film where minute variations of grain size etc have minimal impact in any actual print, versus high magnification of something
like 35mm using a condensor system, for example. Different perspectives on the problem; but mine in basically practical, despite all that
time spent with the densitometer. I want visible results in the print, and am not trying to write a textbook.

So, according to Gerald Koch, D-76 is the correct formation as far as activity optimization is concerned; i.e., 28:72 = 2:5 almost precisely. - David Lyga

David Lyga said:

So, according to Gerald Koch, D-76 is the correct formation as far as activity optimization is concerned; i.e., 28:72 = 2:5 almost precisely. - David Lyga

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It also points out the balancing act involved with devising a developer formula. This is sometimes forgotten when people tinker with formulas.

The activity curve for an MQ or PQ developer is U- or V-shaped. The ratio representing maximum activity lies at the bottom of the curve. Varying the ratio in either direction results in a lowering of activity.

If you are not a pro avoid frustrations by using XTOL. Change film format or stock for sharpness, grain, tonality and speed adjustments.

Gerald C Koch said:

There is an optimum ratio between the two developing agents where developing activity is at a maximum. For an MQ developer this ratio is M:Q = 28:72 weight for weight. For a PQ developer this ratio is P:Q = 7:93.

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Adding this to the back pages of my copy of The Darkroom Cookbook, 3/e.

Richard Jepsen said:

If you are not a pro avoid frustrations by using XTOL. Change film format or stock for sharpness, grain, tonality and speed adjustments.

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He learned by a different path the same lesson I learned. Save yourself the hard journeys and use replenished XTOL.

David Lyga said:

So, according to Gerald Koch, D-76 is the correct formation as far as activity optimization is concerned; i.e., 28:72 = 2:5 almost precisely. - David Lyga

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Hi David

Gerald's post on optimum ratio for super additive only described the ratio, the amount, the pH, the sodium sulphite, remain to be decided.

Ian's database of 'clones' and variations can be reviewed

http://www.lostlabours.co.uk/photography/formulae/developers/devD76_variants.htm

As well as Ilfords changes on the path to Microphen - on same site

If you step wedge you may get results like Foma's page 2

http://www.foma.cz/en/fomapan-400

So next question?

There are 24 pages on the kinetics of development in Mees and James that cover this but they do not answer even such a straightforward question as why phenidone gives more shadow detail than metol, as measured by effective EI.

Xmas said:

Hi David

Gerald's post on optimum ratio for super additive only described the ratio, the amount, the pH, the sodium sulphite, remain to be decided.

Ian's database of 'clones' and variations can be reviewed

http://www.lostlabours.co.uk/photography/formulae/developers/devD76_variants.htm

As well as Ilfords changes on the path to Microphen - on same site

If you step wedge you may get results like Foma's page 2

http://www.foma.cz/en/fomapan-400

So next question?

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Then too there is probably the "most important" factor and that is the bottom line. In the past phenidone was expensive so the optimal ratio was not always observed.

Alan Johnson said:

There are 24 pages on the kinetics of development in Mees and James that cover this but they do not answer even such a straightforward question as why phenidone gives more shadow detail than metol, as measured by effective EI.

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Even before the discovery of phenidone it was known that developing agents varied in how well they worked to develop the latent image. Inorganic agents such as iron sulfate and sodium hydrosulfite cause a marked loss in emulsion speed. Even some of the organic ones also cause a speed loss like paraphenylenediamine.

Mees is a bit out of date. If there is an answer to your question then it is most likely in Grant Haist's two volume work.

Gerald C Koch said:

Even before the discovery of phenidone it was known that developing agents varied in how well they worked to develop the latent image. Inorganic agents such as iron sulfate and sodium hydrosulfite cause a marked loss in emulsion speed. Even some of the organic ones also cause a speed loss like paraphenylenediamine.

Mees is a bit out of date. If there is an answer to your question then it is most likely in Grant Haist's two volume work.

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Yes but David is going to need a step wedge to see the 1/3 of a stop or fog level Microphen gives.
The only real reasons to switch or stay is for skin problems or risk off or availability.

Well, for years I have been using my personally devised formula for B&W film. It is rather odd, in that I use very little of each component, but works fine and lasts forever if, and ONLY if, stored in either glass or PET plastic bottles, filled completely. Thus stored, its activity remains consistent.

To make one liter of (one shot) developer:

6g sodium sulfite, anhy
0.5g Metol
1.25g HQ
2.5g sodium carbonate, mono

This translates into the volumetric (for those not having scales) as follows:

4ml sodium sulfite, anyh
0.67ml Metol
2ml HQ
2ml sodium carbonate, mono

You might have to adjust the carbonate (up or down), as this film development formula might be a bit too active. But it produces fine negatives with excellent shadow detail. Amazingly, it can even be diluted up to three times if wanted. But, regardless of dilution, always use 'one shot'. I use high temps (up to 90F at up to 1+2), so you might wish to use with no dilution at your lower temps in order to obtain reasonable development times. The canard about there not being enough devoloper within the solution in order to do justice to the consistency I find much overstated. These meager amounts of developer work more than adequately when used 'one shot'.

For prints, I simply increase the Metol by one half, double the HQ, and increase the carbonate to 15g (or 12ml). Obviously, the number of prints at this effective dilution will not be as great as with Dektol 1+2. - David Lyga

Looks like a simple and economic formula, David. Do you have any sample developing times for this "Lygadol"?