Divided D-76?

What is it?

 

What is different from D-76?

 

Tell me your experiences.

 

Thanks.

The idea is to help tame out of control contrast. Just for numbers sake, it you have a scent that has a 10 stop contrast range and your film is only capable of recording 5 stops.

 

The film is placed in the developer for a short time, say 1/2 to 1 minute, then removed and placed in an accelerator bath, in this case borax solution.

 

The developer will exhaust itself in the areas where a great deal of light fell, the highlights. The developer will continue to work on the areas where the light was not so bright, the shadows.

 

This process can be repeated as many times as necessary. The result is a negative that has a wider useable contrast range.

 

It's a lot of work, mostly trial-and-error, and usually only used for large format work where you develop each shot individually. I have used it with D-23 just for the experience, and it does work.

 

It's much easier to use a low-contrast developer, like POTA, that will give you more repeatable results.

 

Ted

<p>Ted is partially correct. Divided, or more accurately, two-bath developers

are good for compensating highlights and thus are particularly well suited for high contrast

scenes and contrasty films.  Divided D-76 is simply a two-bath version of

the classic developer.</p>

<p>But, I would disagree that they are a lot of work, require trail & error and

only suited for large format (single sheet film).  In fact, one of the

beauties of two-bath developers is that they are very simple to use and work the

same no matter what film you have (assuming you are shooting at or near normal

rated film speed).  You use the same development times whether you are

shooting Tri-X, FP4+, Fuji Acros, Delta 400 or virtually any other B&W film. 

And, it is virtually impossible to overdevelop and very hard to underdevelop. 

True, you have two baths, requiring you to fill & dump one extra time, but how

much simpler can this be?  In addition, the development time in each bath

is typically 3 minutes, sometimes high as 5 minutes per bath (contrary to the

30-60 seconds indicated by Ted), which in total is less than many one bath

developers.  So, you can actually save some time!</p>

<p>Other advantages:</p>

<ol>

<li>Good accutance with moderately fine grain (and if you start with a fine

grain film, it's even better)</li>

<li>There are several formulas available, offering additional control over

grain and accutance</li>

<li>Solutions can be reused, providing good economy (1 L of bath A will

process 20 rolls and 1 L of bath B will process 10 rolls)</li>

<li>Long tonal scale</li>

<li>Suitable for <u>all</u> film formats (not just large format)</li>

</ol>

<p>Disadvantages:</p>

<ol>

<li>Unless you go with Diafine, you have to mix solutions yourself from bulk

chemicals (which however are readily available)</li>

<li>Two-bath developers are not suited for low contrast scenes</li>

<li>Two-bath developers cannot be used with zone system shooting (i.e., N+1,

N-1, etc.) since degree of development is essentially fixed</li>

<li>As indicated above, they cannot be used with pushed (or pulled) films</li>

<li>Not a good choice if you prefer higher contrast negatives</li>

<li>First bath typically requires continuous agitation (but hey, it's only 3

minutes!)</li>

I cannot agree that two-bath developers cannot be used for pushing or pulling film. It may be the case with Diafine, but for example Tetenal lists development times for pushing with Emofin. And divided D-23 is really D-23 with an alkaline second bath, so the time in the first developer obviously influences the contrast.

I have never tried divided D-76, so I do not know how it would respond to increaed time in the first bath, but with 100 (or 50 in Vestal's version) grams of sulfite, I would be surprised if there is no development in the first bath.

Yes, I suppose for a given 2-bath formula, like Tetenal EMOFIN, you can push films, but for most formulas, you get minimal speed as you increase bath times simply because the way a 2-bath developer works. Once the developer is exhausted (in Bath B), it's exhausted, and adding more time to Bath A doesn't substantially add more developer into the emulsion (especially with thin film emulsions). So, point is that you can't use the same two bath formula to both push a film and develop the film at its normal speed. You must switch developers.

I should say "...you get minimal speed INCREASE as you increase bath times..."

If you want to push the film, you go back into the developer for another 30 sec and then back ino the accelerator until the developer is exhausted again. Most film allows you to view the film with a dim dark green safelight for a few seconds during development. If it doesn't look dark enough, go for another round.

 

If you are going to push the film you would be better off with a tanning developer as it toughens the emultion in the developed areas and helps to keep the fresh developer from penetrating.

 

The reason this is mostly used for large format is that you usually don't need to use this process on the whole roll. If you are going to shoot a whole roll in a high contrast situation, why not use a lower contrast film and save yourself the grief.

 

Ted

"Once the developer is exhausted (in Bath B), it's exhausted, and adding more time to Bath A doesn't substantially add more developer into the emulsion (especially with thin film emulsions)."

 

That's right. But divided D-23 has D-23 as the first bath, and D-23 will develop film all by itself. Emofin bath A will also develop by itself. You seem to assume that essentially no development takes place in the first bath. This is correct for some divided developers, but not for all. I have tried some versions of divided developers with metol and very little sulfite in the first bath, and a very alkaline second bath, and the contrast in this case is indeed pretty independent of the time in bath A, but I have had severe problems with uneven development. If anyone has a good formula for a divided developer in which no development takes place in bath A, I'm interested.

You are absolutely correct, Ole-Hjalmar, some development does occur in Bath A, and such depends on the concentration of sodium sulfite, which raises the pH to kick off development. The D-23 variations have relatively high concentrations of sulfite (100 g/L). Other formulas I have seen have low concentrations (e.g., 10 g/L). Vestal's version of divided D-76 has 50 g in Bath A (and also 50 g in Bath B).

 

That said, the sulfite is not a very strong alkalai and so development can be slow, starting with the highlights. It's not till the second bath with the stronger alkali that development takes off and shadows start to develop.

 

I have not had problems (yet) with uneven development.

"I have not had problems (yet) with uneven development."

 

Any formula you would recommend? Of the home-brewed stuff I have used divided D-23, Stoeckler, and Thornton developers, all variations of the same really. In addition I have used Thornton's developer with 40 g sulfite added to the second bath, which makes it pretty close to a metol-only version of Vestal's divided D-76, actually. They all work well, but I am curious about formulas with less development in the first bath.

Ole-Hjalmar,

This is what I am working with presently (Beutler variation):

 

Bath A Metol 6.5g sodium sulfite 35g water to make 1 ltr

 

Bath B sodium carbonate 12g water to make 1 ltr

 

Agitate continuously in Bath A. Agitate continuously for 30 sec. and then for 5 sec every 30 sec. thereafter in Bath B.

 

For Fuji Acros 100 (EI80), I do 5 min. in Bath A and 4.5 min in Bath B. Grain is superb, accutance is wonderful, and tonality is comparatively long and flat (great for Acros' inherent higher contrast).

 

The low sulfite limits development (in Bath A)/grain solvation, and the stronger alkali in Bath B promotes sharpness/adjacency effects. In general, the lower sulfite and enhanced compensation is what appeals to me personally. D-76 1:3 is next best, but my tests show this 2-bath is markedly better (with Acros).

 

Hope this helps!

"Bath A Metol 6.5g sodium sulfite 35g water to make 1 ltr

 

Bath B sodium carbonate 12g water to make 1 ltr "

<snip>

"Hope this helps!"

 

Thanks for the info. The developer I get very uneven development with has 10 grams/liter of metol, and 2-3 grams/liter sulfite in bath A, and approximately 10 grams/liter of sodium hydroxide for bath B. It's the metol version of the Pextral pyrocathechin two-bath developer described here: http://www.apug.org/forums/forum224/33269-pextral-s-two-bath.html

 

The development is close to zero in bath A, and proceeds very rapidly in bath B, which may explain the uneven development. Your formula seems to be an interesting compromise. I have some Foma 100 I would like to experiment a bit with.

With the fast acting sodium hydroxide, I would think you would need very good agitation to avoid uneven development. The low sulfite in Bath A could cause a big pH swing when going to Bath B, which might create some issues as well.

 

Let me know how your experimentation works with this formula. I suppose you could drop the sulfite even more to reduce development in Bath A and improve sharpness, but I don't think I'd go less than 10 g/L.

I have run a quick test with Foma 100, and under a 10x loupe, the grain seems to be no bigger than Thornton's version with 80g/l of sulfite, but a bit sharper, and still very pleasant. With the flatbed scanner the difference is not that pronounced, perhaps a little less mushy and a bit sharper. I should have used my Scanmate 5000 instead of the flatbed of course, but it's still buried in the basement behind a ton of furniture from my mother's house.... Seems to be a very nice developer. Thanks a lot.<div></div>

Crop of the above image<div></div>

Looks good to me too! Excellent sharpness, fine grain and good shadow detail. Thanks for the feedback!

Russ,

I recently tried your two bath formula/method for Acros. THe results were great in every respect. I calibrated your gram measurements as follows:metol - 1 tsp + .5 tsp + .25 tsp + .125 tsp ( or 2 tsps with 1 eigth tsp taken away ), sulfite - 1 tbs + 1 tsp + .125 tsp, sodium carbonate - 2 tsp