Contrast capability of developers

[david_lyga]

<p>I do not know if anyone wants to 'go here' but I do have a question that is covered only rather peripherally in the literature. It involves the contrast capabilities of B&W developers. Let's take MQ developers initially: which of these three components MOST and LEAST influences contrast capability of a developer: 1) alkalinity 2) MQ ratio 3) dilution. We all know that gamma increases with time and temperature and agitation. That is not what I am after. Essentially, what I am after is the emergence of shadow detail before the highlights get blocked (essentially an increase in film speed). And the three factors I noted are supposedly important in this regard. I need to know just how important. Also, does the presence of a restrainer (potassium bromide or benzatriazole) effectively reduce film speed (by suppressing the shadows as well as intended base fog)? These are matters that I have never seen definitively parsed. If you wish to expound upon other developer constituents feel free to do so, but I did want accurate and final answers on the MQ type of developer. Thank you all. - David Lyga. </p>

[john_elder1]

<p>You should buy and read Steve Anchel's Darkroom cookbook, Film Cookbook, Adam's The Negative, and perhaps most importantly Photographic Materials and Processes by Stroebel, Compton, Current, and Zakia( RIT's Text for the chemistry and physics of photography) Anchel's books will tell you what most chemicals will do and their function in the devlopment process. RIT's book will answer(probably with more detail than you want) every question you are concerned with. You are confused about some things and I am not going to write a paper explaining them to you. However, if you are looking for " emergence of shadow detail before the highlights get blocked" what you seem to be describing is a Compensating Developer. A compensating developer exhausts the development in the highlights while continuing development in the shadows, by definition. It however DOES NOT increase contrast, it reduces contrast. A typical compensating developer, and most ofter used for this purpose, is Rodinal. Used 1 part developer to 100 parts water with infrequent agitation and you get the development you are describing. However you lose film speed. You gain high accutance. And if the film is exposed properly you get great shadow detail. There have been many post recently where the OP suggests or indicates that Rodinal is being used to "PUSH" film development. Rodinal is the wrong developer for that purpose. All developers have 4 components: 1 Developer, 2 Restainer, 3 Accelerator, 4 Preservative. Read the above books if you want to find out how to manipulate each of these 4 components to achieve what you want. I mix my own paper developers. I buy film developer. LOL</p>

[chris_waller]

<p>I'd also recommend reading 'Developing' by Jacobson and Jacobson, and 'Elements' by Barry Thornton.</p>

[jpo3136b]

<p>Okay, I'll take a shot at this. I think alkalinity would affect how soft the print would be. For an example of this, I would say that D76 used as a paper developer will yield a very soft, almost completely grayish print. pH=9. Most paper developers that punch out the blacks will have an alkalinity around 10 or 11.</p>

<p>Coincidentally, I have found with homemade developer that pH 9 will cruise the film to really good results. Higher pH in film developers will yield really dense, high contrast negatives. pH at 10 or 11 will do well for papers. Shifting alkalinity around can have an observable effect; but, it is not always efficient to just try to alter the acid/base of the solution. Like, D76 with sodium carbonate will make a paper developer that will work better than just D76; but D76 and sodium carbonate will not look just like DEKTOL. Comparing a modified D76 to a known paper developer recipe will suggest that it's not just alkalinity that yields the contrast; it contributes, but the structure and influence of the other components also have an effect.</p>

<p>Alkalinity seems to have the most readily observable influence on contrast, but it is not the only contributor.</p>

<p>If it is part of the solution, it's going to somehow to contribute to not just one aspect, but the overall quality of the results.</p>

<p>MQ ratio. I wouldn't touch it. I would recommend either use existing MQ ratios with known effects, or use single component developers. Really, MQ devs seem only to increase the speed with which the developers work. On the whole, my guess from observations is that they come out about 5X faster than either Metol or Hydroquinone alone.</p>

<p>Dilution. I believe that dilution affects the speed with which the developer acts. For an example, look at how dilution increases extend development times. I think dilution could affect contrast but in a very limited way; like, it is possible to dilute a solution so much that a print will not print evenly; or, so thin that there is little or no action regardless of time; or, in great strength, developers can yield such dense blacks so fast that there appears to me almost no gray.</p>

<p>The four components. Keep in mind, this doesn't mean one has to have four ingredients. It's possible to remove the restrainer quite easily; in my homemade developers I've had more problems with using restrainers than anything else. Tired of it; I just threw them out completely. Whenever I consider using one, the whole recipe gets thrown off. One need not look to my foibles; Kodak D23 would be an example.</p>

<p>Restrainers. When using single component developers, they're not really useful as far as fog prevention.</p>

<p>Preservatives; I recently began adding Borax to one of my favorite homemade recipes. The recipe leads with sodium sulfite, but it has a limited preservative influence. If left out, I can see the hydroQ and sodium carbonate oxidize up immediately (forms a brown solution and residue on contact). But, that doesn't mean that a preservative will extend the shelf life of a solution. Interestingly, by adding some Borax to my favorite recipe, I have been able to extend the life of the solution by double its without-Borax three day lifespan. It may last even longer. We'll see. And, as it does oxidize, that oxidation occurs at a very slow rate with a precipitate instead of just coloring up the whole solution. Point is, different preservatives will act in different ways. And, in the case of Borax, I noticed it did affect contrast.<br>

Borax solutions will usually test out about pH 9; but there is a heckuva lot of sodium carbonate in my recipe, so I feel a lot of its alkalinity influence gets overridden. It's just overpowered by the quantity of sodium carbonate (pH10+).</p>

<p>The solution's pH remained close to the same (if it lowered, I couldn't notice it with pH paper); but the ability to yield midtone grays improved considerably. Adding Borax took my homemade recipe from a quick-acting high contrast developer that added a stop's worth of energy to a slower acting one that needed a stop's worth more of light, but could yield grays a lot easier. I like it, and will probably continue to use that recipe for a little while. Coincidentally, to make room for the Borax in the solution, I cut accelerator (sodium carbonate) by a third to one half (would have to check my notes). So, less accelerator and more preservative (Borax) led to prints with a wider range that could be attained more easily.</p>

<p>My answers aren't definitive; these are just the trends I've noticed as I was tinkering around. I thought about a similar question one time; and, I wondered if the best way to get a good data set would be to just build a simple developer and then test it extensively while altering the proportions per run. This would be very repetitive, and not meet my immediate needs, so I never did pursue it in a way that could generate a good, scientific data set.</p>

<p>Good luck on your project. I'd sniff around over at APUG. Some of those guys seem to chat about this sort of thing a little more. J.</p>

[jpo3136b]

<p>Hey, for most to least influence over contrast, I'd suggest the list in the order that you had it: alkalinity, developer composition/MQ ratio, and then dilution. I really believe dilution to be a distant third. Alkalinity a hard first.</p>

<p>MQ ratio is, I believe, a red herring. It's basically an accident that the stuff turned out to be a superadditive developer. In working with single component developers, I cannot see why someone would want an MQ. I know everyone does; but I think this may have only been a real advantage through commerce; one person could say his MQ recipe cut time; that'd be about it. Metol-only developers look nice.</p>

<p>Really, hydroquinone-only developers look just as nice as anything else to the point where I don't know why anyone would go to the expense to tinker with Metol, except for commercial purposes. Hydroquinone is a great compound, and I would clearly bet on it before MQ. Metol-only D23 is nice, but I have been able to achieve a test strip or two that I thought looked just as good with hydroquinone instead, but it takes about 1 1/2 to 2 times as long.</p>

<p>HydroQ rocks.</p>

<p>Dilution is really a lot better for coping with temperature or staying above or below a given development time. In fact, if one thinks about the idea that any negative development can be stopped at any point in the process by immersion in running cold water; and then the process can be resumed again a moment later; well, dilution looks like it would do a better job of stopping more than promoting anything. Anyway, good luck.</p>

[david_lyga]

<p>Thank you all. John (O'Keefe-Odom) your profound answer was very interesting but I do take polite issue with your categorization of Borax as a preservative (let me know if I am incorrect). I understand this to be an accelerator (less powerful than Kodalk or, of course, sodium carbonate). I believe that it has no preservative power at all. (Am I wrong?). But your comment about the change in mid-tone separation is very interesting and needs to be explored. However, again, I take modest issue with your admonition not to change the MQ ratio. I have a very old (1953) edition of a comprehensive guide to various manufacturers' formulae and there is an amazing disparity among the various film and paper developers in this regard. The ratios for paper vary from 1 + 9 (always favoring HQ) to only 1 + 2. And these are not 'soft' paper developers. Thus, this 1 + 4 ratio obtained in D-72 cannot be sacrosact. I do have the excellent 'Developing' by Jacobson and Jacobson but do not have the others. The Focal Encyclopaedia of Photography I also own and there are many discussions about this but, definitively, I'll bet that there really is not a way to enhance shadow detail without allowing the highlights to block, except through the practical 'exhaustion' method from 'stand developers' or maybe dilutions so extreme where the highlights have no chance of blocking. I do not know the true answers but folks like you do add to the subjective (and objective) equation and I thank you for that. Perhaps my text was ambiguous to a fault: I know that 'compensation' means, in effect, increased film speed (because shadows will be 'encouraged' and highlights will be 'suppressed' with the overall contraction of values. My extensive experimentation does not really mitigate my enduring confusion though. I have used a simple metol and sodium sulfite developer, have added sodium carbonate, and have achieved all the contrast one could ask for. And I have added sodium bicarbonate (to slow down the development) to a highly diluted Dektol and have, in fact, achieved rather 'soft' results with film. Thus, paradoxically, the higher contrast developer can act softly and vice-versa. BUT, here is the conundrum (because I am not a chemist): when developed to the SAME GAMMA (ie, contrast) by varying time, PH, or even MQ ration, there seems to be NO DIFFERENCE with emerging shadow detail. In effect, are 'speed producing' developers really just a myth? I fail to see quantitative differences but, also, know that my knowledge is very limited here. I do love doing this and have an intrinsic 'need' to capture 'time' with film. There is something magical about this 'capture' - David Lyga.</p>

[jpo3136b]

<p>I categorized Borax as a preservative solely because I have seen the solution with it in there last longer. That's it. Not a big deal to me; a rose is a rose by any other name. For the MQ ratios, also not a big deal; what I mean there is that because of their superadditive nature, it could be a little difficult to unlock the pattern of their strength through simple tabletop testing. Thus, I mentioned, stick with the known ones; world's not going to collapse . . .</p>

<p>No difference in emerging shadow detail? I wonder what you mean by "emerging", but I guess it doesn't matter. I imagine it is shadow detail that just borders on underexposure to black. I would imagine that you would see a loss of this. It seems to me that by increasing contrast that one would at least lose some of the details because there would be less of a range of gray within those details. </p>

<p>As I think about this, I wonder if this is one of those cases where one could confuse exposure and contrast. Idea being that exposure would drive a gray, but contrast would be an overall relationship of grays. I would have to think about that some more. </p>

[conrad_hoffman]

<p>The more rigorously I matched CI, the less difference I could find between developers. Any developers. Compensating developers probably exist, but they were more of a marketing wish, than an effective solution (no pun intended) to a problem. My efforts at highly diluted developers (Xtol) resulted in early shoulders and low Dmax, but weren't very satisfying. There is a limit. People have beaten the standard developing agents and common formulas to death, with surprisingly little gain. IMO, if you want a radical difference, you need to go pretty far off the beaten path. I had some fun with PPD and vitamin C based formulas, but for reasons of grain size and structure, not compensation. For an interesting general read, if you can find access to them, try the various articles in the BJP by Crawley back when he was doing the FX series.</p>

[john romano]

<p>Get a copy of "Beyond the Zone System" from The View Camera Store. After reading it, check out what else Fred Newman has in his store. I guaranty it will open your eyes to B&W photography that you never knew before.</p>

<p>Testing, testing, and more testing. Only one sure way to measure the results. It will show in your work.</p>

[david_lyga]

<p>John O'Keefe-Odom: yes, 'my 'emerging' was ambiguous. I should have used 'threshhold'. I meant the beginning of density above base fog. Having done so many tests (with single frames because I cannot afford rolls and rolls of film just to do a test) I have come to a like conclusion with Conrad Hoffman that there simply might not be a developer that can give a better threshhold in density (or at least one that I do not know of). UNLESS......I am coming to the conclusion that 'clean' negatives (ie, without base fog) actually contribute to slower film speeds. Why? Restrainers, or even developer constituents that contribute to low base fog, also 'attack' or suppress this threshhold exposure density. That makes sense: this low density is in the same league with base fog. I guess, then, that the question remains is this: is there a developer that will actually enhance (encourage) base fog density (and, with that, also promote this threshhold density that is part of the actual exposure). I have not tried Phenidone but I understand that it is a more 'fog prone' developer and needs HQ and a restrainer in order to suppress this non-exposure base fog. But maybe that is the answer: more Phenidone, less HQ. less restrainer. Just a thought from one who is far from attaching a real scientific legitimacy to my efforts. But I am sure that the real answer has long been decided upon before my mediocre testing. - David Lyga.</p>