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  1. #21

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    Quote Originally Posted by Maine-iac
    A print in a one-bath developer will continue to develop as long as it's left in that bath. The contrast will continue to increase, the shadows will become darker and darker.
    Larry
    This is not true. In one bath development of prints, the print will quickly reach the maximum contrast and Dmax. The print largely stays there, btu hugely excessive development can only increase fog and decrease shadow contrast.

  2. #22

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    Quote Originally Posted by Ryuji
    This is not true. In one bath development of prints, the print will quickly reach the maximum contrast and Dmax. The print largely stays there, btu hugely excessive development can only increase fog and decrease shadow contrast.
    My standard print developer for years has been Zone VI print developer, diluted 1+2. I believe that it's very similar to Dektol. (I use it because it's what I started with years ago, and I haven't had a good reason to switch.) My standard practice was to develop Ilford MG FB for 2 minutes at 70F. A while ago, though, I decided to speed match the various contrast grades gotten through my color head. To my surprise, I only achieved grade 3.5. In trying various things, I finally considered extending the development time. A four minute development time gave a maximum contrast grade of 4.5. More extended development didn't help.

  3. #23
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    Larry, the FB papers also probably have them incorporated, but my Luminos paper does not. Nor do several others, but I don't have the list handy. I'll see if I can find it, but if not, I'll have to retest.

    The developing agent diffuses outward and reduces in activity with time I suspect, giving less boost to development. In fact, this is why some newer papers are resistant to overdevelopment, as the developing agent in the paper is used up.

    As for split development of color materials, I have found that due to diffusion out of the layers is quite variable, I found crossover in both split development and in development with a water rinse following the developer. The yellow (top layer) stops developing fastest and the cyan is slowest to stop in some cases. In any event, in my experience, the results were not very good.

    Use what works for you.

    PE

  4. #24
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    Quote Originally Posted by Photo Engineer
    Larry, for the most part modern B&W papers have incorporated developing agents in them. If you use a 2 bath developer, the developing agent washes out in the first bath and therefore imparts a change to the characteristic curve that might be unanticipated.

    To test if your paper has incorporated developer, take some 1% NaOH (sodium hydroxide) solution, and put a drop on a piece of the fogged paper in question. It will turn either black or grey denoting a high or moderate level of developing agent. Of the half dozen or so papers I have, about 1/2 are with developing agents and 1/2 are without. For example, Kodak Polycontrast IV turns black, and Ilford MGIV turns grey.

    BTW, this will also affect the keeping characteristics of the papers concerned. Even refrigeration or freezing might not delay oxidation of these incorporated developers. Only time will tell, as this is rather new to some paper types, and is moot with Kodak B&W papers.

    PE
    Years ago I used a stabilization processor to speed things up. I always fixed the prints immediately. When the processor broke down once, I used a strong carbonate solution in a tray with equal success. It was, of course, Kodak stabilization paper, double weight.
    Gadget Gainer

  5. #25
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    Quote Originally Posted by outofoptions
    I have wondered about this. My experience is that if I hit the exposure right on the paper, I can leave it laying in the one bath developer a long time with no noticeable difference. Most folks seem to talk about paper as if it were film, but that is NOT MY EXPERIENCE AT ALL. Minimum time for maximum black exposure and you can cook that sucker for a long time. At least that is my experience.
    Ryuji is correct and the quote above expresses the essence of what happens in the tray with almost all current papers (Kodak, Ilford, Agfa, Fuji, etc).

    Modern papers have a self limiting factor due to the high chloride content, and the nature of the incorporated addend and developing agents (if present). I have demonstrated this to myself over and over by observing what is stated in the above quote.

    Some papers do not observe this behavior though and that is why we see a difference of opinion here among the posts. Papers made without some of the contrast control agents, developing agents, toners and etc will exhibit a different response in a given developer.

    PE

  6. #26
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    Quote Originally Posted by Photo Engineer
    Ryuji is correct and the quote above expresses the essence of what happens in the tray with almost all current papers (Kodak, Ilford, Agfa, Fuji, etc).

    Modern papers have a self limiting factor due to the high chloride content, and the nature of the incorporated addend and developing agents (if present). I have demonstrated this to myself over and over by observing what is stated in the above quote.

    Some papers do not observe this behavior though and that is why we see a difference of opinion here among the posts. Papers made without some of the contrast control agents, developing agents, toners and etc will exhibit a different response in a given developer.

    PE
    I'm learning something from this post. I confess that I haven't used a single-bath developer for at least twenty-five years of printing. It may well be that newer emulsions have changed sufficiently that the effects I described don't happen anymore. Back in the day, the print used to gain both contrast and density the longer it remained in the developer. That's one of the reasons I switched to divided developers, though the main reason was to eliminate the need for temperature controls since I was in Malaysia and found it difficult to keep my chemicals under 85F, even with a window-unit air conditioner.

    I may try the single bath again and test my papers in it.

    Larry

  7. #27

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    Quote Originally Posted by Peter De Smidt
    My standard print developer for years has been Zone VI print developer, diluted 1+2. I believe that it's very similar to Dektol. (I use it because it's what I started with years ago, and I haven't had a good reason to switch.) My standard practice was to develop Ilford MG FB for 2 minutes at 70F. A while ago, though, I decided to speed match the various contrast grades gotten through my color head. To my surprise, I only achieved grade 3.5. In trying various things, I finally considered extending the development time. A four minute development time gave a maximum contrast grade of 4.5. More extended development didn't help.
    That story sounds like the developer is quite dissimilar from Dektol or any standard print developer of that type. Your developer is most likely low in pH, high in bromide, low in developing agent concentration, or perhaps combination of these. Ilford MG FB in fresh Dektol 1+2 will reach asymptotic curve within 2 minutes at 20C. Also, unless you used grade 4.5 or 5 filter, it is very strange that you even got grade 4.5 by longer development. Print emulsions are developed to completion, or until the sensitometric curve reaches asymptote. At that point no further development will buy you extra Dmax or contrast. Huge excess of development can only bring you troubles.

  8. #28

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    Quote Originally Posted by outofoptions
    I have wondered about this. My experience is that if I hit the exposure right on the paper, I can leave it laying in the one bath developer a long time with no noticeable difference. Most folks seem to talk about paper as if it were film, but that is NOT MY EXPERIENCE AT ALL. Minimum time for maximum black exposure and you can cook that sucker for a long time. At least that is my experience.
    This is correct.

    Intrinsic contrast of emulsion is often called "gamma infinity." This is the maximum value of gamma one can obtain by developing that emulsion for a very long time. This value depends on the developer but no pictorial emulsion developer can offer a drastically high gamma infinity from the same emulsion. That is, gamma infinity is rather a property of the emulsion to a large extent. (This is often not a quantity directly measured but it is a value obtained by extrapolation of experimental data.) Gamma infinity is determined by the statistical distribution (relative frequency) of sensitivity of individual grain. If an emulsion contains 1 part very fast emulsion, 1 part fast emulsion, 1 part medium speed emulsion, 1 part slow speed emulsion, wherein each of which has fairly high gamma infinity, the resulting emulsion will have much wider distribution than any of the ingredients alone, hence a lower gamma infinity. Once mixed and speed-frequency distribution is broadened, there is no way to reverse it (or to increase contrast).

    Modern b&w camera negative emulsions typically blend 3 or more raw emulsions and have gamma infinity of 0.8 to 1.5 range. However, these emulsions are generally developed to much lower gamma (usually average gradient of 0.6 or so) by truncating the development way before the emulsions reach the gamma infinity. In the case of negatives, it is advantageous for several reasons.

    On the other hand, enlarging paper emulsions do not receive quite the same degree of blending to lower the contrast, and the gamma infinity is a few times higher. These emulsions are developed until the gamma infinity is practically reached. There is no advantage in truncating development for prints.

    This is the reason behind your observation.

    Before c. 1985, the method used to make emulsions were quite different from that today. Well, I won't bore you with this story today. Also, in early decades of silver gelatin, negatives had higher contrast than today. Regardless of these, the basic idea is same. Even in very old darkroom instruction books, prints are developed to completion.

    There is one exception to the statement I made above about there is no way to increase gamma infinity by changing the developer. Lith developer containing hydroquinone as the sole developing agent can increase gamma beyond gamma infinity achievable with ordinary developer. There's another class of modern high contrast developers containing hydrazine derivatives and optionally including amine contrast booster compounds. However, these come with considerable cost in image quality for pictorial purposes.

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