PMK or Pyrocat HD for enlarging 4x5 negs?

[lee\c]

I use Pyrocat HD 2+2+100 use a Durst 138s with condensers and print on various VC papers. I use a green filter for soft and a blue filter for the hard printer. Obviously I split filter print. How does this new found info work for me?

lee\c

[Jay DeFehr]

Hi Lee.

If you've developed a system that works for you, stick with it. The problem is that it's very difficult to scale your negatives to a particular Exposure Scale, or paper grade by trial and error methods unless the YFE is neutralized. Otherwise the Exposure Scale of the paper keeps moving around with negative development, and doesn't stabilize until it's bottomed out at grade 0, which requires a needlessly dense and contrasty negative. You could eliminate the green filter from your workflow, and allow the negative itself to act as the low contrast filter. Start with a base exposure with no filter, and then find the time for the exposure with the magenta filter that gives you the best print. If your print is overexposed before it reaches optimum contrast, reduce the base exposure and start over. A few iterations should get you where you want to be. Again, the problem is in scaling your negatives. How do you curently scale your negatives?

Jay

[sanking]

Jay.

1. I have tested with both VC filters and with a BES 23-CII enlarger with a color head.

2. You may consider yourself a serious printer, and that may or may not be true. In any event, I did not say you were not a serious printer. However, your insistence that pyrogallol stain is the same as pyrocatechin stain on VC papers is just plain wrong. If step wedge negatives are developed in pyrogallol and pyrocatechin developers to the same CI, as measured by blue light densitometry, they will print identically on graded papers but they *will not* print identically on VC papers with the same filtration package, unless you increase magenta filtration to the point where all light to the low contrast green layer of the emulsion is blocked. One could adjust filtration so that at some point they print the same, but they will not print the same with the same filtration package, unless light to the green layer is blocked.

3. The shape of the curve, which you describe as one of the "non-essential characteristics" is very important. The fact that the densities match at any two or three points on the curve does not tell you the full story of toe and shoulder shape. For that, you must look at the plotted curve.

4. There is a fundamental error of concept in the way you are using the color analyzer, IMO. Balancing the color so that what you call the yellow filter effect is neutralized does not necessarily convert the color to neutral "as far as the paper is concerned" because the the analyzer does not know what color is neutral to the paper. The actual color to which the paper is neutral may be weighted heavily toward the blue, or toward the green. And analyzer only tells you what it sees, not what the paper sees.

5. The concept of the YFE may have some use, but the more important issue is the color of the exposing light. VC papers are sensitive to light that peaks at two wavelengths, one the green, another in the blue. Many people expose VC papers with two light systems, one blue and one green, and match contrast to the number of units of exposure of each that are applied to the paper. Try printing the step wedge negatives developed in pyrogallol and pyrocatechin developers to the same CI using the same units of blue and green light and see what happens.

Sandy King

[brian steinberger]

So, if I run tests to determine personal film speed test, and development time using a staining developer, say I get my personal EI (assuming .1 above fb+f) now want to test for development time. I shoot a few zone VIII exposures and enlarge the negatives to lightest tone visable on paper, what grade do I use? And how does the stain not affect the results of the Zone VIII test?

If you read a zone VIII density though a densitometer to eliminate the yellow stain and come up with an appropiate density for VC paper (1.29) but then go to print with this density, due to the stain wouldn't the results would come up short (due to highlight compression)?

Sorry if I'm confusing. Do you understand what I'm trying to ask?

[sanking]

Hi Lee.

You could eliminate the green filter from your workflow, and allow the negative itself to act as the low contrast filter.

Jay

How much potential contrast control would you have using only the stain in the negative. For example, in an example you gave earlier where step 1 measures 1.23 by blue channel densitometry, how much of that density is stain? Probably not much more than .20, right?

By contrast, a #1 yellow filter blocks more than twice that amount, easily over log .040. It would seem to me that one would have a lot more potential control with the filter than the stain in the negative.

But I don't use the kind of split color printing so perhaps I am missing an important point here.

Sandy King

[Jorge Gasteazoro]

If step wedge negatives are developed in pyrogallol and pyrocatechin developers to the same CI, as measured by blue light densitometry, they will print identically on graded papers but they *will not* print identically on VC papers with the same filtration package, unless you increase magenta filtration to the point where all light to the low contrast green layer of the emulsion is blocked.

Everybody that has tested these developers and done this with VC papers knows this. To keep arguing about this is an exercise in futility. Jay is never going to be convinced and there is no argument that we can present that will do so.

[sanking]

Everybody that has tested these developers and done this with VC papers knows this. To keep arguing about this is an exercise in futility. Jay is never going to be convinced and there is no argument that we can present that will do so.

Well, I am going to bow out of the thread at this point. As I indicate, I have complete data to support my own conclusions, and will eventually publish the data, after it has reviewed by the two persons who agreed to work with me on the pyro project. So eventually everyone can look at the results and test for themselves to verify or repudiate the methodology and conclusions.

I assume Jay will also try to publish his data and conclusions. However, I would recommend that he have it reviewed by someone else who understands the sensitometry of pyro developers before doing so.

Sandy

[Jay DeFehr]

Hi Sandy.
[QUOTE]
I guess when you wrote:

I can tell you for certain that the color of the stain does indeed matter when printing on VC papers, and virtually every serious printer who has ever compared results with pyrogallol and pyrocatechin type developers knows this to be the case.

I took it to mean that you don't consider me a serious printer, since I absolutely disagree with you on this subject.

1. I have tested with both VC filters and with a BES 23-CII enlarger with a color head.

Perhaps you could explain why you chose to use Yellow + Magenta filtration for your tests with the color head? The bottom line is that without a color analyzer, you can't accurately neutralize the YFE.

If step wedge negatives are developed in pyrogallol and pyrocatechin developers to the same CI, as measured by blue light densitometry, they will print identically on graded papers but they *will not* print identically on VC papers, unless you increase magenta filtration to the point where all light to the low contrast green layer of the emulsion is blocked. One could adjust filtration so that at some point they print the same, but they will not print the same with the same filtration package, unless light to the green layer is blocked.

Sorry, but this is not true. Negative density X will print density Y on VC paper regardless of the agent responsible for the stain when the YFE is neutralized. there is no need to develop to a specifc CI to test the neg density v printing density, and it introduces all kinds of variables that have nothing to do with the experiment.

3. The shape of the curve, which you describe as one of the "non-essential characteristics" is very important. The fact that the densities match at any two or three points on the curve does not tell you the full story of toe and shoulder shape. For that, you must look at the plotted curve.

You've misunderstood me. The shape of the curve is most certainly non-essential when the object of the experiment is to determine whether matching densities as determined by blue channel densitometry produce matching print densities with VC papers using the same filtration. Remember, we're debating the effect of the color of the stain on VC papers, not the working properties of the developers.

4. There is a fundamental error of concept in the way you are using the color analyzer, IMO. Balancing the color so that what you call the yellow filter effect is neutralized does not necessarily convert the color to neutral "as far as the paper is concerned" because the the analyzer does not know what color is neutral to the paper. The actual color to which the paper is neutral may be weighted heavily toward the blue, or toward the green. And analyzer only tells you what it sees, not what the paper sees.

There's no error of concept. As I stated in an earlier post, most light sources require neutralization even without a negative in the carrier. This is a simple calibration procedure. With the light source neutralized according to the analyzer, neither more green, nor more blue, a stepwedge is printed on the VC paper in question, and the Exposure Scale of the paper determined by reflection densitometry. When the Exposure Scale measures in the grade 2 range, it indicates a neutral light source. You're making this more complicated than it needs to be.

5. The concept of the YFE may have some use, but the more important issue is the color of the exposing light. VC papers are sensitive to light that peaks at two wavelengths, one the green, another in the blue. Many people expose VC papers with two light systems, one blue and one green, and match contrast to the number of units of exposure of each that are applied to the paper. Try printing the step wedge negatives developed in pyrogallol and pyrocatechin developers to the same CI using the same units of blue and green light and see what happens.

I've covered these issues already, but will repeat myself here; the color of the exposing light is neutral, as determined by the calibration procedure noted above. It comes as no surprise to me that neutral to the color analyzer is also neutral to the VC paper, and once the YFE is neutralized, the exposing light is neutral, and the color of the negative is neutralized, pyro and catechol negs print identically. To test the effect of the color of the stain on VC papers, it is just common sense to isolate the color as a variable, and introducing non-essential characteristics into the experiment invalidates the results. These are practical, hands-on results, and not theory dependant on undefined peak spectral sensitivities. I've done the work, and I'm confident in my results. This information has never been presented, and is of great value to those printing stained negatives with VC papers, despite your unfounded objections. In my opinion you're doing a disservice to users of staining developers by trying to obfuscate the concepts involved.

Jay

[Jay DeFehr]

Everybody that has tested these developers and done this with VC papers knows this. To keep arguing about this is an exercise in futility. Jay is never going to be convinced and there is no argument that we can present that will do so.

Hi Jorge.

Sandy has commented many times that an in-depth investigation of the effects of stained negatives with VC papers has not been done. I've done the work, so I won't be persuaded by erroneous information based on flawed experimental design, no matter how long it's been propogated, or by whom. I've pointed out the flaws in Sandy's methodology that explain his flawed results, if you'd like to post your testing methodology, I'd be happy to analyse it for errors as well. The goal is good information, not maintanence of the staus quo.

So, if I run tests to determine personal film speed test, and development time using a staining developer, say I get my personal EI (assuming .1 above fb+f) now want to test for development time. I shoot a few zone VIII exposures and enlarge the negatives to lightest tone visable on paper, what grade do I use? And how does the stain not affect the results of the Zone VIII test? If you read a zone VIII density though a densitometer to eliminate the yellow stain and come up with an appropiate density for VC paper (1.29) but then go to print with this density, due to the stain wouldn't the results would come up short (due to highlight compression)?

Hi Brian.

you've identified the problems very well, and they are some of the reasons printing stained negatives on VC papers have been so frustrating for so many. Due to the YFE, your paper's Exposure Scale moves around with negative development, so trying to calibrate your system is like trying to hit a moving target. To get useful exposure and development information from your tests, your paper's ES must be constant, and the only way to do that is to neutralize the YFE with magenta filtration. To do so precisely requires the use of a color analyzer/timer. If you don't have an analyzer/timer, I recommend doing your calibrations with graded paper. Once your calibration procedure is complete, it can be transferred to VC paper by matching the graded paper's Exposure Scale by adding magenta filtration. Once this is done, you can increase or decrease print contrast by increasing or deceasing magenta filtration to fine tune your prints. It might seem like an unnecessary complication to use a graded paper for calibration when you intend to print on VC paper, but if you don't have a color analyzer/timer, it will save you much frustration and wasted time and material trying to hit that moving target. I hope this makes some sense, but if it doesn't let me know and I'll try to clarify.

Jay

[Jorge Gasteazoro]

I'd be happy to analyse it for errors as well.

This assumes you know what you are doing and have experience in experiment design. So far, the arguments you have presented only tells me you dont understand color theory and filtration and your basic premise that the stain does not matter is flawed. We have tried to show you where you are wrong but you wont listen in your unshakeable beleif that you alone are right.

In a nut shell, two different color negatives project two diffrent light spectra on the paper, VC paper reacts differently to these two kinds of spectra even if you dont want to beleive it.

I am sorry Jay, but I doubt there is anything you can teach me about experiment design, so I will decline your offer to check my work for errors, better and more prepared people than you have done this.