D-76 dilution: Only to save money, or for other reasons?

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kcf
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D-76 dilution: Only to save money, or for other reasons?

Post by kcf » Mon Feb 12, 2007 12:15 pm

Does greater or lesser dilution of D-76 have any effect on the way the negative looks, or is dilution strictly for saving money?

A) Can D-76 be turned into a compensating developer with dilution?

B) Used undiluted does D-76 become a high-speed developer?


Ornello
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Re: D-76 dilution: Only to save money, or for other reasons?

Post by Ornello » Mon Feb 12, 2007 1:35 pm

kcf wrote:1) Does greater or lesser dilution of D-76 have any effect on the way the negative looks, or is dilution strictly for saving money?

2) Can D-76 be turned into a compensating developer with dilution?

3) Used undiluted does D-76 become a high-speed developer?
1) Yes. Slight compensation, slight increase in graininess and sharpness

2) Yes. See above

3) No. Exactly the opposite.

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OK, Ornello

Post by kcf » Mon Feb 12, 2007 2:14 pm

A) Is a high-speed developer then the same thing as a compensating developer? The phrase "high--speed" would seem to have thrown me.

B) Undiluted D-76 would then be a low-speed developer?

C) Undiluted D-76 would be an appropriate substitute for Microdol-X, Rollei Low-Speed or Ilford Perceptol?

D) Does diluted D-76 or any other compensating, high-speed developer have any other purpose than push-processing?

My understanding at this point is there are two basic directions: low-speed, which will reduce grain and increase resolution and sharpness, and high-speed, which will increase graininess and reduce sharpness, but will add speed. Adding speed is developing shadows while preventing highlight build-up. When you dilute D-76 or Rodinal you are pursuing the same effect to be obtained by Pyro or T-Max or Xtol. When you use it undiluted you are pursuing the same effect obtained by Microdol-X, etc.

And I am assuming (perhaps incorrectly) that you, Ornello, will have no use for high-speed developers since you do not push.

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Re: OK, Ornello

Post by Ornello » Mon Feb 12, 2007 4:11 pm

kcf wrote:A) Is a high-speed developer then the same thing as a compensating developer? The phrase "high--speed" would seem to have thrown me.

B) Undiluted D-76 would then be a low-speed developer?

C) Undiluted D-76 would be an appropriate substitute for Microdol-X, Rollei Low-Speed or Ilford Perceptol?

D) Does diluted D-76 or any other compensating, high-speed developer have any other purpose than push-processing?

My understanding at this point is there are two basic directions: low-speed, which will reduce grain and increase resolution and sharpness, and high-speed, which will increase graininess and reduce sharpness, but will add speed. Adding speed is developing shadows while preventing highlight build-up. When you dilute D-76 or Rodinal you are pursuing the same effect to be obtained by Pyro or T-Max or Xtol. When you use it undiluted you are pursuing the same effect obtained by Microdol-X, etc.

And I am assuming (perhaps incorrectly) that you, Ornello, will have no use for high-speed developers since you do not push.
A) No.

B) No. Standard speed

C) No. Those would give finer grain, less speed.

D) Diluting D-76 provides slight compensation, which has nothing to do with pushing. Pushing is a waste of time. It does not work.

Some developers that use Phenidone rather than Metol (Acufine, UFG, Microphen) give a slight (1/3 stop) increase over 'standard' developers such as D-76 or ID-11, etc. Both are 'solvent' types, which use a solvent (such as Sodium Sulphite) in the developer to reduce the clumping of grain. These Phenidone-based developers are almost identical in composition to D-76 with the exception of their developing agent.

Here is a an Ilford Phenidone formula that is supposed to be very similar to Ilford's unpublished Microphen formula:

http://www.digitaltruth.com/techdata/ilford_id68.php

Here is D-76:

http://www.digitaltruth.com/techdata/kodak_d76.php

You'll note the similarities. Does the ID-68 give more speed? Perhaps 1/3 stop more, with a bit less fine grain.

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Post by kcf » Mon Feb 12, 2007 4:31 pm

A) What is meant by "speed"?

B) What is meant by "compensation"?

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Post by kcf » Mon Feb 12, 2007 4:38 pm

A) I think you are also saying that since D-76 uses a solvent to reduce clumping just as the high-speed developers, that it does not produce highlight build-up any faster than they do.

B) And metol has nothing to do with controlling highlight build-up.

C) So (and I know you do not like push) am I mistaken in thinking T-Max is giving me less highlight build-up when I push (or at any other time) than D-76?

D) Is high-light build-up mostly related to dilution, temperature and time, and not so much to which developer one uses?

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Post by Ornello » Mon Feb 12, 2007 4:43 pm

kcf wrote:A) I think you are also saying that since D-76 uses a solvent to reduce clumping just as the high-speed developers, that it does not produce highlight build-up any faster than they do.

B) And metol has nothing to do with controlling highlight build-up.

C) So (and I know you do not like push) am I mistaken in thinking T-Max is giving me less highlight build-up when I push (or at any other time) than D-76?

D) Is high-light build-up mostly related to dilution, temperature and time, and not so much to which developer one uses?
A) It has nothing to do with that at all. The two are not related. Graininess is reduced by partly dissolving the silver halide crystals before they are developed.

B) Not entirely true. Metol is somewhat more sensitive to development by-product suppresion than is Phenidone.

C) I doubt that you would see any difference, but if there would be any, D-76 would probably give less dense highlights.

D) Yes, primarily. It has little to do with dev composition.

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Post by kcf » Mon Feb 12, 2007 8:20 pm

Ah, I see what you are saying there, the clumping of grainis reduced by the solvent. You were talking about graininess being reduced by the solvent, not high-light build-up.

Well, it has been my understanding that T-Max is a compensating or, actually, a semi-compensating developer and the word compensating means that it reduces the accumulation of black on the negative to control blown-out highlights while still developing the shadows. Is my understanding of the word compensating incorrect?

The reality is probably that stopping down sufficiently when shooting is the only way to control blown out highlights.

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Post by Ornello » Tue Feb 13, 2007 11:18 am

kcf wrote:Ah, I see what you are saying there, the clumping of grainis reduced by the solvent. You were talking about graininess being reduced by the solvent, not high-light build-up.

Well, it has been my understanding that T-Max is a compensating or, actually, a semi-compensating developer and the word compensating means that it reduces the accumulation of black on the negative to control blown-out highlights while still developing the shadows. Is my understanding of the word compensating incorrect?

The reality is probably that stopping down sufficiently when shooting is the only way to control blown out highlights.
Compensating development is the use of greater dilution than 'normal' to control excessive highlight density and contrast, rather than shortening development time, which reduces contrast overall. Compensating development has little influence on shadow contrast, but mostly affects highlight density and contrast.

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Post by kcf » Tue Feb 13, 2007 4:47 pm

I can understand wanting to diminish highlight development, but what is meant by reducing overall contrast?

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Post by Ornello » Tue Feb 13, 2007 5:01 pm

kcf wrote:I can understand wanting to diminish highlight development, but what is meant by reducing overall contrast?
Overall contrast is determined by length of development, all other things being equal.

By reducing developer concentration and increasing duration, the developer weakens more in the highlight areas than in the shadow areas. During development, by-products are formed by the breakdown of silver bromide into silver and bromine. Bromine is acidic, and where it forms (at the surface of the film) it inhibits the action of the developer (which is alkaline). On the other hand, in the shadow areas, where not much bromine is formed, little inhibition occurs. Thus, shadow contrast is less affected by dilution that highlight contrast.

Understand?

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Post by kcf » Tue Feb 13, 2007 8:28 pm

I think so. The silver bromide breaks down into two components when exposed to longer but diluted development: silver and bromide. Bromide, an acid, inhibits the action of the developer, an alkaline. Where there is more silver bromide built up on the negative from exposure to light when the picture is taken, in the highlights, more bromide forms on its surface during long diluted development, inhibiting the action of the alkaline developer. Where there is less silver bromide formed on the negative from exposure to light when the picture is taken, in the shadows, little or no bromide forms during development to inhibit the action of the developer, so development continues as normal.

Now, I think you are going to say that longer diluted development is appropriate when you shoot a film faster than its true iso. But I do not know that, so I will ask, when do you dilute developer?

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Post by Ornello » Wed Feb 14, 2007 10:20 am

kcf wrote:I think so. The silver bromide breaks down into two components when exposed to longer but diluted development: silver and bromide. Bromide, an acid, inhibits the action of the developer, an alkaline. Where there is more silver bromide built up on the negative from exposure to light when the picture is taken, in the highlights, more bromide forms on its surface during long diluted development, inhibiting the action of the alkaline developer. Where there is less silver bromide formed on the negative from exposure to light when the picture is taken, in the shadows, little or no bromide forms during development to inhibit the action of the developer, so development continues as normal.

Now, I think you are going to say that longer diluted development is appropriate when you shoot a film faster than its true iso. But I do not know that, so I will ask, when do you dilute developer?
Silver bromide breaks apart into silver and bromine when exposed to light, but only a few atoms in the crystal are affected. Developer continues and amplifies this process. It is this breakdown of silver bromide into insoluble solid metalic silver and soluble bromine (a liquid) that forms the image. Without developers, much more exposure would be required. Developers multiply the action of light millions of times. That's why we use them.

When developer begins working, it 'liberates' a lot of bromine from heavily exposed areas, but only a little from shadow areas. When the developer is used full-strength, this bromine has little effect, since the strength of the developer is rather high. When the developer is used in dilute form, it becomes much more 'sensitive' to the action of the liberated bromine ions.

During development, it is customary to 'agitate' the tank to distribute the by-products of development throughout the developer and remove them form the surface of the film, where they cause streaks if left undisturbed. This 'streaking' is caused by the fact that the bromine is denser and heavier than the developer solution. Being acidic, it inhibits the action of the developer where it is present. As it slowly sinks down the surface of the film, it creates a path of reduced density in its wake. On the print, these appear as dark streaks. Gentle agitation once or twice per minute prevents these streaks.

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Post by kcf » Wed Feb 14, 2007 2:25 pm

Side note: Didn't nineteenth-century photographers put glass plates in the sun for long periods? Was that to develop them without chemicals? Breakdown of silver bromide using only light?

Side note 2: Isn't there a nineteenth-century process called bromine or bromide? Has a lithographic look to it.

The only thing I have ever heard dilution associated with is pushing, or, at least, shooting fast and then wanting to reduce highlight development. The problem is graininess. But you are telling me longer development times produce more consistent results. So, dilution might be better if pulling causes you to have a very short development time. Might be better to use T-Max in more diluted form and go, say eight minutes instead of five in stronger form.

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Correction

Post by kcf » Wed Feb 14, 2007 4:15 pm

Well, since the temperature of T-Max has to be increased with dilution, it may not be the best example to use to discuss different uses of dilution. But maybe D-76 should be diluted at times merely to give a longer processing time for more consistent results. And I think you have implied that is a use for dilution. Am I understanding you correctly?

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