Anchell and Troop also elaborate on this in "The Film Developing Cookbook." This has been discussed before here. As I recall someone (Adrian B.?) posted the results of an experiment they did that showed that development activity did indeed go down when the volume of working solution was reduced below the amount recommended by Anchell and Troop
For whatever it's worth, I'm very confident that this differs for different developers.
Kodak has recommended dilution at 1+1 for D-76 and Xtol since flashbulbs were the standard for supplemental light (or since Xtol was introduced). This goes for 35 mm in a single reel tank as much as for 120. Hundreds of thousands of photographers have gotten good results from this dilution, and my swear by D-76 1+2 or Xtol 1+3, despite that (in 35mm minimum volume) giving significantly less than Kodak's recommended minimum "active developer" volume. For other developers, you'll normally dilute much more than that -- Rodinal, for instance, is typically used at 1:25 or 1:50, sometimes 1:100. So, given Anchell didn't specify which developer he meant, we can only take what was quoted above as more of a rant than a recommendation.
I'm sure this has been covered before but I couldn't find a thread. Anyway, reading The Darkroom Cookbook I came across to this...
"According to the Kodak Research Lab it only takes 150.0ml of developer to cover the surface of 80 square inches of film and to develop that film. What is missed by some is that the research that led to this finding was carried out to determine the bare minimum of developer that could be used in a Kodak Versamat machine processor in order to maximize profits to the last penny. What is also missed is that there is a difference between minimal development and full development of a negative or roll of film. What is further missed is that Kodak’s final conclusion was that while 150.0 ml could develop 80 square inches of film, far better results would be obtained by using a minimum of 250.0 ml of undiluted developer.
The one thing all photographers can do to instantly improve the quality of their negatives and guarantee full and complete development of every negative on a roll of film or batch of sheet film is to increase the volume of developer that they routinely use. The bare-bones minimum that should be used to develop 80 square inches of film is 250.0ml of undiluted devel- oper. This means that if you are developing a single roll of 120 in a two-reel metal tank and using 500.0 ml of D-76 straight (undiluted), you are in good shape as you are using double the minimum. However, if you are developing two rolls of 35 mm 36-exposure film in the same two-reel metal tank you are back down to 250.0ml per 80 square inches.You will obtain consist- ently better results were you to remove one roll of film, replace it with an empty reel as a spacer and use 500.0 ml of developer—it is not possible to use too much developer, and more is always better."
I've been developing film for years now, first with Paterson tanks, then a Jobo with both kinds of reels. Years ago I settled on XTOL 1:1, so always using a little more than 100ml of active developer per roll.
Anchell refers to work by the Kodak Research Lab about amounts of developer needed. But I have not seen I citation for that research. It would be great to access the original source if anyone knows where it could be found.
Has anybody experimented with using more developer than the minimum and seen a difference? I've never heard about minimal development and full development or a negative. Nobody really talks about that.
Now for the highlighted part... this is just commentary... why would Kodak recommend that amount (100ml minimum per 80 square inch) if it was going to be used as well for home use, then Kodak would not be maximizing profit, if anything people would be saving money and not buying more Kodak developers.
Doremus your supposition that,"And [large developer volume], it would almost necessarily eliminate compensating development techniques, in which the developer is planned to exhaust before highlights are "fully developed." is something I have wondered about. For example, if one is using 1 + 100 dilutions of Rodinal and long development times to try to achieve a lot compensation by causing the developer to be locally exhausted in highlight areas, wouldn't it be good to have a weak working solution and by that logic actually minimum volumes of developer would be best? But I have never heard an exception to the rules about the recommendations about minimum developer required in the case of high dilutions and long development times. According to the logic of what you are saying one should be carefully scaling the volume of developer to kind of effect wanted. But I have not heard a reputable source say that would be a good idea. Nor have I heard that large developer volume is an impediment to compensating effects. Anchell and Troop say it is impossible to have too great a volume of developer. But I don't know why. So I wonder if the idea of using a weak solution in order to promote local exhaustion is somehow independent of the need of having an adequate volume of developer. Perhaps it is about a difference between local exhaustion and the overall exhaustion of developer. Perhaps the assumption that a greater volume of developer must be "stronger" and acts more like a less diluted solution is not valid.I would imagine that the amount of developing agents in a particular amount of solution (at whatever dilution) needed to "fully develop" 80 sq inches of film depends a lot on developer formulation (pH, superadditivity, etc.) as well as the particular developing agents used (Metol, hydroquinone, ascorbic acid, glycin, pyrogallol, catechin, etc.)
It would also depend on the "standard" for "fully developed" (whatever that is supposed to mean).
And, it would almost necessarily eliminate compensating development techniques, in which the developer is planned to exhaust before highlights are "fully developed."
If developer activity stops before you get the film speed, shadow density and highlight density you need, then, yes, you likely need more developer. If not, then...
Doremus
I am not sure what you are referring to about "The Darkroom Cookbook" having bad information. But in these cases, it is better to go beyond personal opinion to some kind of empirical facts. You said that we should use manufacturer recommendations but Anchell (and Troop) claims that there has been confusion about what Kodak actually recommended about developer volume. He said Kodak's empirical research showed was 150 ml/roll was just a bare minimum that skinflint commercial processors could use to obtain marginally acceptable results. But he said that very same research proved that 250 ml/roll would yield "much better" results. So Anchel could say he was citing manufacturing recommendations but that historically the recommendation that the larger volume was better got lost in the shuffle and 150 ml became accepted as plenty good in popular lore. Anchel and Troop make a strong assertion based upon reputed Kodak science. But to my knowledge, they do not offer not a citation for the Kodak research. I would agree that is not ideal and would be much better if we could access the primary source he refers to. But there are other sources of objective information. I was persuaded when an APUG member, maybe Adrian, did an experiment that showed that developer activity did deteriorate at lower volumes.I recommend treating the Darkroom Cookbook as a reference source for the various, mostly ancient recipes, should one choose to try them. The rest of the book contains quite a bit of bad information.
Follow Kodak’s and Ilford’s directions/tech pubs.
I am not sure what you are referring to about "The Darkroom Cookbook" having bad information. But in these cases, it is better to go beyond personal opinion to some kind of empirical facts. You said that we should use manufacturer recommendations but Anchell (and Troop) claims that there has been confusion about what Kodak actually recommended about developer volume. He said Kodak's empirical research showed was 150 ml/roll was just a bare minimum that skinflint commercial processors could use to obtain marginally acceptable results. But he said that very same research proved that 250 ml/roll would yield "much better" results. So Anchel could say he was citing manufacturing recommendations but that historically the recommendation that the larger volume was better got lost in the shuffle and 150 ml became accepted as plenty good in popular lore. Anchel and Troop make a strong assertion based upon reputed Kodak science. But to my knowledge, they do not offer not a citation for the Kodak research. I would agree that is not ideal and would be much better if we could access the primary source he refers to. But there are other sources of objective information. I was persuaded when an APUG member, maybe Adrian, did an experiment that showed that developer activity did deteriorate at lower volumes.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?