Contrast control via dilution

All, I've heard about a few developers that let you control contrast by changing dilution. I've recently run into F76 from Clayton, and one of my photo teachers mentioned that her husband does the same thing with D23.

How exactly does that work? Doesn't changing the dilution also affect sharpness and grain? I know I've heard that in reference to D76 and ID-11. Or are some developer forumlae such that the grain and sharpness stays the same regardless of dilution, but the time changes? If so, what types of developers _aren't_ like this (ie - because of a formula that cannot maintain grain and sharpness through dilutions)?

What other developers are like this?

thanks
allan

I use HC-110 for the majority of films and vary the dilution rather than time or temperature in order to change the contrast of the film. I've incidentally found that I get fewer instances of agitation pattern effects by using shorter times and a stronger developer. I try to adapt my working solution to produce results in 5 to 6 minutes development time.

Although I've not precisely tested the contrast index change for the films I use now, I generally develop in dilution A to obtain higher contrast than the recommended dilution B for negatives intended for alternative process printing. For example, HP5+ has a recommended development time of 5 minutes in dilution B at 68F and ISO 400. Instead, I'll give 5 minutes in dilution A if I intend to print that negative as a van dyke brownprint for instance.

At one point I did extensively test the old TMAX emulsions for regular silverprinting using dilution as the basis of affecting contrast index and I standardized on a time of 6 minutes. I would vary the dilution by 5 parts water in order to produce contrast changes and this worked well.

When Kodak changed the emulsions a few years ago, I did some preliminary tests with TMY 35mm and found the following:

Dilution 1+24 produced a Contrast Index (CI) of .63 (about N+1/2 for me);
Dilution 1+31 ("B" from the concentrate) gave a CI of .55 (about N-1/2 for me);
Dilution 1+39 produced a CI of .48 (about N-1 for me).

All the above are at 68F for 6 minutes. EI 320 looked to be about right for N development and there was about a 1/2 stop loss in film speed between the 1+24 and 1+39 dilutions. From these results and using an EI of 320, "Normal" looked to be about 1+29 dilution for 6 minutes @68F. To vary the contrast upward from this point I would decrease by 5 parts water for each 1 stop push so that 1+19 would probably give N+1 or thereabouts. This system works well for me (for expansions in particular) and I really like the fact that development times can be standardized to a shorter convenient time.

I've never been very concerned about a sharpness or grain difference using various developers as long as the speeds are reasonable. So, I've never really compared the effect of this method on grain size. I've never found the resultant grain disturbing though. I do like TMY vs TMX as I think the former is inherently sharp and the latter mushy. Grain has never really bothered me because I see it as an inherent artifact of the photographic enlarging process. If anything, I would exploit films with pronounced grain for effect rather than try to minimize grain through choice of developers. (I did this for awhile with Diafine for example and coarse-grained emulsions such as 2475 which bit the dust several years ago much to my dismay.)

If I want smaller grain, I use a larger camera and film and contact print.

Joe

As another example, I used HC110 with tri-x film in a jobo. my development time was always 5 min at 68. for low contast scenes I used a full oz. of hc110 stock mixed with a quart of water. normal scenes three quarters oz. and high contrast scenes only one half oz. the system worked well. the idea, of corse was to exhaust the developer in the highlights while continuing development in the shadows.

jdef said:

Non-solvent developers include Xtol, HC110, Rodinal, PC-TEA, PMK, etc. By diluting these developers, and without changing any other development parameters, contrast is reduced, due to the decrease in developer activity. Care must be taken to use the minimum amount of stock solution required to develop a given quantity of film, regardless of dilution.

Jay

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Jay,

Actually, XTOL is considered to be a solvent developer. It contains quite a bit of Sodium Sulfite (5-10% by mass depending on dilution), as the MSDS for the working solution attests:

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aldevo said:

Jay,

Actually, XTOL is considered to be a solvent developer. It contains quite a bit of Sodium Sulfite (5-10% by mass depending on dilution), as the MSDS for the working solution attests:

Dead Link Removed

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I just looked at the MSDS on the Kodak site (http://msds.kodak.com/ehswww/external/index.jsp and searched by the product number, 8888182 and product name KODAK XTOL Developer) and the 5-10% (by weight) number is the amount of sodium sulfite in the working solution, not the stock solution. The part A solution has 65-70% (by weight) sodium sulfite and the part B solution has 80-85% (by weight) sodium sulfite.

Am I on the right track here?

Hypothesis:

Controlled contrast expansion/contraction can be achieved by altering dilution.

Theory:

If this chart is accurate: And this time is correct:Then these times will all be correct, but the contrast range will vary. As a practical matter, personal film speed and personal development time would be tested for. Tests would be then performed to demonstrate that dilution can be used to control placement of metered Zones VII and IX on a Zone VIII test print.

Thoughts?

Nuthin'?

I think that dilution affects the shape of the curve more so than overall contrast. You can develop to a certain contrast in say XTOL straight and also XTOL 1:2. The two negatives will have the same overall contrast, but the neg developed in undilute XTOL will have more contrast in the highlights whereas the 1:2 XTOL neg will have more contrast in the midtones. To complicate things, the negative developed 1:2 will be slightly sharper and the grain will be larger/more defined due to the reduced amount solvent action of the also diluted sulfite content.

I don't think this is always true with all developers and all films however, esp at extreme dilutions. Some developer/film combos are not capable of reaching a certain CI at a given dilution, whereas a more concentrated developer will produce more contrast.

I'm no an expert though! Maybe someone will chime in with a more thorough explanation....

some more info into the pot from this thread-- (there was a url link here which no longer exists)

Thanks to you both!

Erik, I find that information very interesting. Do you think that rather going with a 5 minute dev. time, a person can test for development time at the stated dilution and use that as a standard time at the various stated dilutions?

Also, that chart basically says that Tri-X hits N+1 at dilution B and 5 minutes. I a bit skeptical of that.

Reading more carefully I see that Gassan was shooting for 1.15 over B+F, for Zone VIII. I think that's thin even for a condensor head and for a cold light head, I'd be looking for something like 1.25.

I can't make sense of his graphs. He's plotting dilution on the horizontal azis and negative density on the vertical axis so the plotted points should reflect development time but he indicates that it's all five minutes.

I'll have to establish my own development time for 1.25 over FB+F in a dilution that makes sense for a time that's not so short, and work from there. I'll probably go with his 1:40.

The main thing is whether he's right that HC-110 can do this. The numbers can and should be confirmed or refuted based on empirical tests.

I didn't follow this thread so sorry this response is way late, but AG chose 5 minutes at the set time, no reason that you couldn't use a longer time, with perhaps a different agitation routine. His point was to keep time and agitation at the constants, and just vary dilution. That is why the graphs show the time as the same, as I'm sure you have worked out. He also went with the 1.15 denstity, that was something he suggested quite steadily, I think part of it was his feeling that 35mm negs printed better on a grade 3 paper, so that was his target, also, I think that this density fit his idea of what a zone VIII should look like. I'm with you, I like something closer to 1.25, but that is the beauty of designing ones own system. As for what he says Tri-x does, well, this is 1970's Tri-x he is talking about, and everyone always said that Athens Ohio water gave shorter development times so who knows-- film has changed, maybe HC-110 has also changed, but you are right, the main thing is that HC-110 can do this, you just have to do the tests to adjust to current materials and your tastes. It is cool to look at things in a different way.

erikg said:

some more info into the pot from this thread-- (there was a url link here which no longer exists)

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Erik,

The wording of your posting in the other thread is a bit confusing. It appears ambiguous (unless you know standard dilutions and do the math) that your post says to mix the 10% dilution, and then dilute that once more at the rate of 1:30 to 1:80, which is certainly much too dilute for the usage. I'd assume that you make the 10% dilution (1 part syrup to 9 parts water), then dilute that 1:2 for a 1:30 final dilution, 1:3 for a 1:40 final dilution, etc. Is that correct?

Lee

That is correct. I apologize if my transcription of Gassan's text is confusing. I'm sure that was my fault. When you stop to think that Kodak's standard "dilution B" works out something like 1:33 (IIRC) then what you say makes perfect sense. I certainly think diluting right from the concentrate makes the most sense. It seems that at the time Arnold wrote the textbook he felt that mixing the 10 percent dilution first would be a convenient time saver, but by the time I worked with him when I was at school he was suggesting that we all go down to the Agway feed store and buy these small syringes so we could measure out the syrup directly. I think I still have one. At the time I don't think you could get a syringe at a drug store in Ohio, that's why the Agway. I haven't used HC-110 in a few years, and I never actually used this contrast control method myself in any extensive way, but I do find it interesting.

erikg said:

At the time I don't think you could get a syringe at a drug store in Ohio, that's why the Agway. I haven't used HC-110 in a few years, and I never actually used this contrast control method myself in any extensive way, but I do find it interesting.

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Syringes were made difficult to get because of IV drug use, as if that would solve the problem. Then scarce needles were shared by people who were HIV positive, so it's now apparently easier to get syringes and needles again. I use syringes from a farm supply store.

Thanks for the clarification on HC-110 dilutions.

Lee

Lee L said:

Syringes were made difficult to get because of IV drug use, as if that would solve the problem. Then scarce needles were shared by people who were HIV positive, so it's now apparently easier to get syringes and needles again. I use syringes from a farm supply store.

Thanks for the clarification on HC-110 dilutions.

Lee

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That is the reasoning I remember. This was in the 80's, afterall. That Agway was a two minute walk from the art building, now I think I'd have to drive some distance to find a farm supply store near me. Where does milk come from again? I'm sure I can find some syringes on the internets.
Thinking about HC-110 reminds me that sometimes I can cause a lot of trouble for myself chasing after something exotic, when what I should be doing is just sticking with the tried and true and getting on with making pictures. But it is good to try new things, right?