Pyro stain v catechol stain re: VC paper [Archive]

sanking

7-Jan-2007, 11:02

Yeah, but you should at least let the thread go awry before you close it, to close it before even one response is posted is an abuse of your powers here. You might be tired of these threads, but I assure "we are all" is an exageration, some of us are not even if the thread does degenerate at the end.

I agree with Jorge. It does not make any sense to ban a thread unless it has gone awry, especially when you allowed the initial information to stand. Why did you not just delete that message and eliminate the thread?

And it may be a presumption on your account in determing that "we are all" weary of these threads. If you look at the last one that was not closed, you will see that it has over 1700 views, which indicates that quite a number of people were not so weary of the subject that they stayed away.

I certainly agree that people should behave with civility, and if they don't their messages should be banned, and if they continue to not act with civility they should be banned. But to close a substantive thread before there is a problem is an abuse of the forum guidelines IMO. If you are going to do that you might as well ban the subject of pyro altogether. Some might like that, but that would not be wise for a forum with so much diversity of opinion.

Sandy King

Marko

7-Jan-2007, 11:38

I agree with Jorge. It does not make any sense to ban a thread unless it has gone awry, especially when you allowed the initial information to stand. Why did you not just delete that message and eliminate the thread?

And it may be a presumption on your account in determing that "we are all" weary of these threads. If you look at the last one that was not closed, you will see that it has over 1700 views, which indicates that quite a number of people were not so weary of the subject that they stayed away.

I certainly agree that people should behave with civility, and if they don't their messages should be banned, and if they continue to not act with civility they should be banned. But to close a substantive thread before there is a problem is an abuse of the forum guidelines IMO. If you are going to do that you might as well ban the subject of pyro altogether. Some might like that, but that would not be wise for a forum with so much diversity of opinion.

Sandy King

Sandy, with all due respect, which in your case is rather significant, let me say the following:

As a relative newbie, I would love to read what the masters of any technique have to say, maybe even ask a few questions once I learn enough to know what to ask.

But the main thing that made me stay away from the entire area of staining developers is, quite frankly, the spectacle of grown-up people bickering like pre-adolescents every single time the topic comes up in any form.

While there are certain participants for whom such behaviour is the norm, everybody involved in this particular area succumbs sooner or later and lets their inner child loose.

I also think that the argument about the sheer number of views doesn't say anything about civility or usefulness of the topic. Just think of it in terms of Jerry Springer Show, because that's exactly what pyro discussions are increasingly becoming.

Regards,

Marko

Jay DeFehr

7-Jan-2007, 11:57

Ralph,

rehashing the same issues is what we do here. Are you going to start closing every thread that revisits previously posted subjects? If not, you're not moderating, you're censoring, and that is beyond the scope of your authority, in my opinion. If you don't want to participate in these threads, I won't miss you, but to deprive the members here of the access to this new, and potentially important information is absurd, and capricious.

Jorge,

510-Pyro is a pyro developer, and its stain is similar to other pyro developers. I sent you some, check it out. Which number step was measured is not important, what is important is that the steps are matched in density, and as you can see, they are. I've gone as far as I care to towards convincing you, since printing stained negatives with VC papers has little relevance for you as a platinum printer. If you're really interested, and not just being contrary, you can perform the experiment for yourself. I postedd the data so that people who hold your opinion in high regard can decide for themselves based on real data and not just hearsay and opinion, no matter how passionately held. I have no desire to get into a long diatribe, and I'm sure Ralph's finger is already on the delete button anyway. I hope this information is useful to those who print stained negatives with VC papers.

Jay

Jorge Gasteazoro

7-Jan-2007, 12:15

Which number step was measured is not important

I disagree with you, it is important and the reason why different stains give different results, as I stated before if your 1.2 density was measured from different steps and not the same step when you dvevloped for the same CI, then clearly the stains have a different response, I cant understand why you are so reluctant to acknowledge this. Once I resolve the issue of spectral film response with the sensitometry I will try your developer, but although you might think the issue is not relevant to me, it actually is since the green vs brownish stain is also important for pt/pd printers. Beleive it or not, yellow/green seems to have a better UV absorption than brownish stains, thus one more fact that supports the notion that different stains are seen differently by the papers used.

Aaron van de Sande

7-Jan-2007, 13:35

Jay it would be best to plot a curve for each of the steps. It is entirely possible you measured a 'crossover point' in the curves.

I tend to agree though that the color of the stain really doesn't make much of a difference.

sanking

7-Jan-2007, 14:53

This is my last contribution to this particular discussion..

Just a few thoughts.

1. The difference between highlight compensation you get with a staining developer like PMK and a non-staining one like D76 is not a dramatic difference. Many people could use these two developers interchangeably and not notice any difference unless someone pointed it out to them. In fact, many people have compared the two for their own work and concluded that the differences are insignificant, or at least not significant enough to make them switch to a staining developer.

2. Highlight compensation itself is a fairly subtle effect. The difference in visual perception of paper white and some texture can be as little as log 0.01. And , highlight compensation that comes with PMK is at the very end of the toe of the paper curve, and therefore not easy to graph.

3. Although subtle, the stain color of a pyrogallol developer like PMK gives “much” more highlight compensation than the stain color of a pyrocatechin developer like Pyrocat-HD. There is both practical experience and spectral data that explains why.

a) First, there is considerable empirical experience from real printers who have compared results and found that there is more highlight compensation with PMK than with Pyrocat-HD. That fact by itself would not be conclusive, but there is also good spectral data that validates the experience.
b) Densitometer readings in Visual (Green Light), Blue, and UV show distinct differences in the transmission of Pyrocat-HD when compared to three different pyrogallol based developers. See <http://unblinkingeye.com/Articles/PCat/PCat3/pcat3.html>http://unblinkingeye.com/Articles/PCat/PCat3/pcat3.html What is most important for this discussion is that the difference between silver density, and silver + stain density, as measured by Visual (green light) and Blue light, is considerably greater for PMK and other pyrogallol based developers than it is for Pyrocat-HD. This clealry implies that the color of the stain of Pyrocat-HD is absorbing much less blue light than that of PMK.
c) The difference in absorption is also supported by spectrophotometer analysis. The results I have seen show that Pyrocat-HD negatives have low absorption throughout the green and all the way in the Blue to around 420 nm. A PMK negative, by contrast, has much greater absorption in the green and blue. The situation reverses in the UV, where the Pyrocat-HD stain has more absorption.

Bottom line is this. A Pyrocat-HD negative developed to exactly the same CI, as read by blue light, will not print on a VC paper exactly as a PMK negative developed to the same CI as read by blue light. The PMK negative will print with more compensation. The Pyrocat-HD negative in fact prints with much less compensation, more like a non-stained negative than a stained one. It may be possible to add filtration so that the two negatives would print the same, but not without changing the characteristics of the curve. Specifically, if you add that much filtration to a PMK negative so that it prints like a non-stained negative, you will lose highlight compensation.

IMO the method of adding magenta filtration to correct for a YFE would be primarily of interest and use to persons who use a pyrogallol based staining developer that has a lot of absorption in the blue and green, not to a pyrocatechin type one that has such a small amount of absorption in the blue and green that analysis by either Visual or Blue light gives almost the same readings. My personal opinion is that if the goal is to change the characteristics of a pyrogallol type developer so that it prints like a non-stained negative, i.e. with little or no compensation, it would be much simpler to just switch to a pyrocatechin one ( Pyrocat-HD, Pyrocat-MC, Diaxactol, etc.) that already prints that way with no adjustment, or to a traditional non-staining formula.

But that is just my opinion.

brian steinberger

7-Jan-2007, 16:24

sanking

7-Jan-2007, 17:36

Sandy,

Besides the stain, what are the other advantages of a pyrocatechin developer (pyrocat HD) over non-staining developers (DD-X, X-tol)? I'm just trying to get a feel for staining developers, besides the stain issue. I understand this now.

A few advantages that come to mind might be the stain masking grain and more edge effects than non staining developers?

Brian,

Pyro staining developers harden and tan the gelatin during development. The two are not necessarily always present together, since some tanning developers do not produce a stain, and some produce a stain that is neutral in color. Tanning itself, where the gelatin is hardened, is responsible for a more precise reduction, which can increase resolution. Tanning also reduces the effects of irradiation (scattering of light in the film emulsion) and infectious development (spreading of silver development beyond the exact image boundaries). This can result in greater apparent sharpness, and is especially valuable when shooting strongly back lighted scenes. Another result is that the negative is desensitized quickly when developed in pyro staining developers, which is an advantage when developing by inspection.

In short, most, if not all of the sharpness advantages attributed to pyro staining developers are due to tanning, not the stain.

Many assumptions are involved, and many persons who have directly compared non-staining developers and pyro staining developers did not find any greater superiority in terms of sharpness. However, the assumptions are based on sound theory of development as can be found in the literature, Haist for example. But a little magic never hurt.

Sandy King

Jorge Gasteazoro

7-Jan-2007, 17:50

The situation reverses in the UV, where the Pyrocat-HD stain has more absorption.

Have you verified this? It seemed to me that ABC was giving me better blocking than Pyrocat, the only reason I did not continued to use it was that it was not good for rotary developing and even with brush development it gave some uneven development.

In another little tidbit, I have a few color print dyes that I use to "dodge" by applying them to my negs, the green dye seems to work better than the orange and or yellow...

sanking

7-Jan-2007, 18:01

Have you verified this? It seemed to me that ABC was giving me better blocking than Pyrocat, the only reason I did not continued to use it was that it was not good for rotary developing and even with brush development it gave some uneven development.

In another little tidbit, I have a few color print dyes that I use to "dodge" by applying them to my negs, the green dye seems to work better than the orange and or yellow...

The graphing from the spectrophotometer testing I mentioned shows that PMK stain has greater absorption throughout the green and blue, but there is a cross-over at 380nm, after which the absorption of Pyrocat-HD stain is greater.

The peak sensitivity of iron-based processes is in the 370 nm range. Peak sensitivity of colloid processes (carbon and gum) is around 360 nm.

I am surprised by your finding with ABC. Is this the old ABC Pyro formula, the one MAS uses? I have found it to have much less absoprtion, both in the blue and in the UV, than either PMK, Rollo Pyro or WD2D+. ABC Pyro is a very energetic developer and with the right film will build a lot of CI very fast.

Sandy

Ralph Barker

7-Jan-2007, 18:56

Jay, Jorge, and Sandy - each of you, along with others, has been warned about your behavior in pyro threads on more than one occasion. Being as none of you seem to have gotten the message, I thought a pre-emptive thread closing might get the message across. While it got your attention, your respective responses were predictable.

Please remember that this is not a government-funded forum in which the right of free speech might be expected to apply. There is no inherent "right" to post here, regardless of how interesting your information or experience might be. Everyone is expected to adhere to the guidelines. Those who fail to do so will be banned, as you've been warned in the past, notwithstanding our reluctance to ban anyone.

The continued bickering does both you, individually, and the cause of staining developers a great disservice, and results in those interested in the topic being forced to sift through fact, fiction, and personality differences. Keep the discussions, even where you have philosophical differences, civil and you'll find the level of moderation . . . well, moderate. Continue the bickering and you'll either be relegated to purgatory (banned) or to a Lounge-like, pyro-only sub-forum with no exposure to the search-engine spiders.

sanking

7-Jan-2007, 19:07

Ralph,

I certainly am well aware of the fact that this is not a public forum and that the owner and moderator can do as they please.

That said, your decison to lecture people publicly is even more unprofessoinal IMO than the bickering you hope to prevent.

Thank you for your attention.

Sandy King

Ralph Barker

7-Jan-2007, 19:32

Sandy - while we seldom comment on administrative issues publicly, the three of you chose to complain publicly, so I chose to respond publicly, rather than just delete your posts as any good, censorship-oriented moderator would do.

Jay DeFehr

7-Jan-2007, 19:55

Hi all.

I’ll try to address your questions as best I can. The idea that characteristic curves should be used to determine the effect of stain color is absurd. To attribute the differences in the printing properties of PMK and Pyrocat HD to any differences in their stain colors is a leap of logic, and an unfounded assumption. By that logic, all catechol developers will produce negatives that when developed to the same CI, produce identical prints with VC papers, and the same with pyro developers. Anyone even remotely familiar with sensitometry should know that’s not the case, for many reasons. Hypercat, a catechol staining developer, produces curves that show significant compensation, while Pyrocat HD, another Catechol developer, produces curves that show little or no compensation. PMK, a pyro developer, produces curves that resemble Hypercat curves more than they resemble Pyrocat HD curves, and 510-Pyro curves resemble Pyrocat HD curves more than they resemble PMK curves. These various curves illustrate clearly how unreliable film curves are for the purpose of isolating the effect of stain color with VC papers.

To test the effect of stain color specifically, it has to be isolated as a variable, and not confused with the working properties of the developer in general. My test does just this, which is why I don’t have to be concerned with curves, or crossover points, or step numbers, or anything but the density as measured by Blue channel densitometry; the basis for sensitometry with B&W films and VC papers. Please understand that I’m not suggesting there are no differences in the colors of the stains produced by pyro developers compared to those produced by catechol developers, just that these differences, whatever they might be, are insignificant regarding printing with VC papers. The issues as they relate to UV processes are likely to be very different, and I make no claims in that regard. Again, matching CIs does not suggest matching curve shapes, and differing curve shapes will produce differing prints. Attributing these differences to the colors of the stains has no basis in sensitometry.

Incidentally, Sandy has advocated the single point comparison method for determining stain intensity, which is the same principle. I believe that those who are interested in the best information, remain open minded and consider these issues without bias will eventually see the rationality in my approach, and the validity of my results. Those who are only interested in protecting their reputations and maintaining the status quo of widespread confusion and misinformation regarding these issues will only seek to obfuscate and confuse the issues, and the users of these materials.

Jay

Aaron van de Sande

7-Jan-2007, 20:02

It is easy enough to poke holes in generalizations about staining developers. Efke films in ABC dry out a green color and then turn tan/brown after a couple of weeks.

Metol/hydroquinone developers also tan the gelatin, one can see the pucker in the emulsion if you look at it at the right angle.

Jorge Gasteazoro

7-Jan-2007, 20:57

Not only have I not been warned, but even if I had been it is the choice of the owner of this site to ban me if he does not want my participation in this site. Having said that, I dont need a lecture from you and I am certainly aware this is a private site, probably before you were aware.

Nevertheless, your "pre emptive" approach sounds more about abuse of privilige than wanting to keep this site free of nastiness. We certainly dont need you to tell us how to behave, you dont want us here ban us, but spare me the holier than thou attitude.

Jay,

Sorry but disagreeing with you it is not as you say:

Those who are only interested in protecting their reputations and maintaining the status quo of widespread confusion and misinformation regarding these issues will only seek to obfuscate and confuse the issues, and the users of these materials.

YOu seem to think you are the only one who has the right answers, I have agreed with you in some things in the past and disagreed with you in ohters, this is one case where I disagre. I think most of us who disagree with you understand that you can vary filtration to make negatives print the same on VC paper, but by that simple admission, the fact that you have to change filtration you are in fact acknowledging that the different stains behave differently.

Jay, Jorge, and Sandy - each of you, along with others, has been warned about your behavior in pyro threads on more than one occasion. Being as none of you seem to have gotten the message, I thought a pre-emptive thread closing might get the message across. While it got your attention, your respective responses were predictable.

Please remember that this is not a government-funded forum in which the right of free speech might be expected to apply. There is no inherent "right" to post here, regardless of how interesting your information or experience might be. Everyone is expected to adhere to the guidelines. Those who fail to do so will be banned, as you've been warned in the past, notwithstanding our reluctance to ban anyone.

The continued bickering does both you, individually, and the cause of staining developers a great disservice, and results in those interested in the topic being forced to sift through fact, fiction, and personality differences. Keep the discussions, even where you have philosophical differences, civil and you'll find the level of moderation . . . well, moderate. Continue the bickering and you'll either be relegated to purgatory (banned) or to a Lounge-like, pyro-only sub-forum with no exposure to the search-engine spiders.

Jay DeFehr

7-Jan-2007, 22:05

Jorge,

I wasn't referring to you, I believe you're sincere in your disagreement. If you look at the data I've posted, you'll see that I didn't vary the filtration, both negs were printed at the same time, on the same sheet of paper, with the same exposure, and the samefiltraton. The point is that when the negs match by blue channel densitometry, they also match regarding filtration required to neutralize the YFE, and produce matching print densities with VC paper. No adjustments were made to match the negatives, the filtration, or the print densities. Clearly, the colors of the stains are not sufficiently different to affect filtration or print densities with VC papers. If pyro and catechol developers produce stains that affect VC papers, how do you prove it? If you suggest comparing developers as different in working properties as PMK and Pyrocat HD, I'm afraid I have to reject that experiment as invalid. It is fundamental experiment design to isolate the variable being tested as much as possible. The single-point comparison is the most conclusive method I could devise, but if you, or anyone else can suggest a more conclusive method, I'm all ears. For any test of the effect of stain color on VC paper to be valid, it must correlate densitometry, contrast filtration, and print density.

I'm confident that if you think about these issues clearly, you'll come to agree with me. Imagine comparing two non-staining developers, one a compensating developer, and the other a non-comnpensating developer by developing negatives to matching CIs, making prints of the stepwedges, and plotting the curves of the printing papers, and then, when the prints don't match, attribute the differences to the colors of the negatives. The issues pertaining to stain color are complicated enough without complicating them further by introducing the general working characteristics of two developers into the equation. This is the only argument anyone has offered to support the contention that the differences in the colors of pyro and catechol stains produce differences in the printing characteristics of VC papers. Differences in spectrophotometry, UV densitometry, or Alt processes are irrelevant except as they apply to the practice of printing stained negs with VC papers, and the anecdotal evidence of printers is only useful if it can be explained, and confirmed in quantifiable terms. Simply saying, "I know it's true because I've believed it to be true for many years, and many have worked under that premise and produced good prints" is not persuasive. Remember, you asked for the data because you weren't willing to take my word for it, and you shouldn't, just as I shouldn't take the word of those who aren't willing or able to provide a rational explanation or supporting data for their arguments.

If you look for information on the differences in the stain colors of pyro and catechol developers and their effects on VC papers, you'll find all roads lead back to Gordon Hutchings, and afterwards, Sandy King, neither of whom have ever published data correlating densitometry, contrast filtration and print density. Almost all of the information that exists on this subject is anecdotal and unsubstantiated, but it's been repeated so long and so often by some supposed experts, and echoed by many others, that it's become accepted as fact. I knew I would ruffle some feathers by sharing my results, but that has never bothered me. At least now there is an alternative explanation and a workable methodology for printing with these materials, and those who go to the trouble to test them will be rewarded with a means for control over their process.

Jay

j.e.simmons

8-Jan-2007, 06:42

I, for one, always find these discussions interesting.

You have all referred to "VC papers" - in the plural. Have any of you done any tests to show that VC papers from different manufacturers react to stained negatives similarly? I'm sure they're not identical, but do you know within a reasonable degree of certainty that they react similarly enough to be lumped together as "VC papers?" Just trying to eliminate variables.
juan

BrianShaw

8-Jan-2007, 10:01

I, for one, always find these discussions interesting.

Me, too.

I have thought about learning/experimenting with staining developers but these discussions (the bickering and on-upsmanship parts) are a bit of a turn-off. For me, so is the detailed science and sensitometry discussions. But these discussions have all taught me something. I think I'll just buy the book and see if I can learn on my own.

steve simmons

8-Jan-2007, 10:27

It is easy to get bogged down in too much information and technical concerns. View Camera did an article on the basics of staining developers in the Sept/Oct 06 issue. It is also available in the Free Articles section of the View Camera web site

www.viewcamera.com

Staining developers can be tested for EI and dev time as described in another article in the Free Articles section as well. Try these articles to get yourself going. You can get more absorbed in the sensitometry later if you really want to.

steve simmons

Jay DeFehr

8-Jan-2007, 11:29

Juan,

any differences in various VC papers' responses to staining developers will be revealed by the methods I've described.

Brian,

unfortunately, there is no "book" that covers this information, which is why we're left to discover for ourselves the best practices, and why there is often disagreement. Sensitometry is an absolute necessity in finding best practices which, once established, will allow users to work by trial and error when preferred. Using Sandy King's "method" will leave you with very overdeveloped, grainy film with much reduced sharpness to print at grade 0, with mandatory highlight compression and virtualy no contrast control in printing, but you can ignore filtration and treat your VC paper like a kind of "special" grade 0 paper. The method I've described will allow you to scale your negatives to any grade, or Exposure Scale within the range of your VC paper, and precisely control the amount of compression at the toe and shoulder, as well as global and local contrast. My method makes full use of the special properties of staining/tanning developers and VC papers for creative expression and the highest possible technical quality.

Sensitometry is an integral part of the photographic process, and you use it whenever you work with light sensitive materials, but you might never have any control over the sensitometric properties of your materials if you don't take the time and make the effort to develop or use a sytem to utilize them in a practical way. The ZS is one kind of system, Phil Davis' BTZS system is another, and many have developed their own versions of these systems, or one of their own to make sense of the sensitometric properties of their materials for predictable repeatable results. In short, you either use a sensitometric sytem, or you work randomly. The system can be relatively good or bad, and its effectiveness will determine the consistency of the quality of your work. It's much easier to learn a simple system that works under a norrowly defined set of conditions, which is why many advocate the use of a single film/developer/paper/developer combination, and feel most comfortable working under specific lighting conditions, all of which make trial and error methods more practical. To each his own, but for those who want a greater degree of control over a wider range of materials and conditions, a working knowledge of sensitometry, and the means to utilize a well defined system is the path to creative expression. I'm only trying to help those who need help by sharing my own experiences and discoveries.

Jay

BrianShaw

8-Jan-2007, 12:13

Steve -- thanks... I've seen those materials and will re-visit them.

Jay -- I understand your point. Perhaps that is my current frustration -- well, current meaning ever since Kodak stopped making Plus-X in 4x5 size. I once had 'a system' that was based in "it works and it works consistently" but without sensitometers, etc. Since then I've had exactly what you describe - inconsistent and random occasional success, with a fair amount of full-out failure - because I can't get "calibrated" with any film I've tried. Let me re-think your comments and go back and re-read the posts; maybe I'll see some personal inspiration that I've been missing as I've been reading them with a "I don't have enough free time to shoot AND do a lot of science experiments" attitude.

Brian

Henry Ambrose

8-Jan-2007, 15:46

I think simply removing the color of the stain is the best way to go for VC printing. One very important reason is that individual films stain differently and with varying color. The color that blocks or allows transmission of light is the problem, not that its stained. A "gray" or neutral stain would not cause any problems on VC paper. It would just be "density".

Of course the next question is "why use a staining developer if you don't want stain?" The answer might be that you want to use one developer for all your film whether its headed for VC, graded or alternative printing. Or it could be that you want the razor sharp grain, possible edge effects and high film speed all in one developer. It might be simply that you have one developer and suddenly want to print on VC paper instead of graded.

Want razor sharp grain with full film speed? Compare Rodinol and Xtol then throw Pyrocat HD into the mix - its kinda the best of both worlds if full speed and sharp grain is what you want. Or it might be high dilutions of Rodinol instead. There's more than one way to skin a cat.

It might be that there's no good reason to use anything but D76 and Dektol. Or Xtol and 130. But there's lots of chemicals out that that do the same job a little differently so why not try them to see what you like? Same reason there is more than one film or flavor of ice cream.

I think that it'd be nice if the proponents of the various magic concoctions would state their own case in the positive instead of attacking one another. I'm tired of the "my densitometer is bigger and better than your densitometer". I find the arguments (the actual words and techniques used to argue, not the discussion) tiring. A gentlemanly exchange would be nice, keeping the sharp elbows tucked neatly to your sides.

Jay DeFehr

8-Jan-2007, 17:11

Henry Ambrose

8-Jan-2007, 18:00

Jay wrote:
"When you talk about "neutral stain", I don't know what you mean. What developer produces "neutral stain"?"

None that I'm aware of. My point is that its the color not the stain. Until the color stops interfering with the VC operation of the paper and enlarger filtration its going to be a potential and unpredictable problem.

Graded paper sees a colored stain as density. VC paper sees colored stain as density AND some filtration depending on the stain color.

All this is my opinion and not backed up by extensive experimental research, but rather just some darkroom time. But I can tell you that colored stain does effect filtration for sure. How much and what wavelengths I can't say other than (obviously) wavelengths that VC paper is sensitive to.

Shine green light through a standard negative onto VC paper and make a print, next shine the same green light through a yellow/brown/orange/olive negative and you will get a different print from the first. To complicate matters further, the stain color is not the same through all portions of the negative so you get a different effect in different parts of the image.

This can be a problem if the print looks like something you don't want. Parts with stain shift, parts without don't. Parts with more stain shift shift more than parts with less stain. The print looks "funny" - that's what I noticed from actually making prints.

How's that for technical?

Jay DeFehr

8-Jan-2007, 19:39

Hi Henry.

It's just occurred to me that you probably haven't read the other thread, in which I describe my system for printing stained negs with VC papers, and which addresses the issues you've raised here. That thread was closed by a zealous moderator, along with my follow-up thread that wasn’t even left open to replies. Links to both threads are below. Thank you for lending your experience and perspective to this discussion, and I hope you’ll read the threads linked below.

Jay

http://www.largeformatphotography.info/forum/showthread.php?t=22188

http://www.largeformatphotography.info/forum/showthread.php?t=22255

Henry Ambrose

8-Jan-2007, 20:33

Jay,

I have read the threads and I had even posted in earlier ones where y'all got to fightin' over this. (that's southern english in case you're wondering)

Its the proportional stain that throws this whole thing haywire. There's no way to adjust it out. (other than to physically remove the color) You might get it out at one combined point of exposure/development/stain but then at other points it is a different value in proportion to the silver density - so you're stuck. And even if your color analyzer would do the trick you're moving to a place where you print B&W with a color analyzer? Not practical at all IMO, even if it did work.

You've got this big "filter" (the stain if you can imagine it existing separately from the silver density) over your negative that varies in strength over its area. You can't fix it all at once. Overall stain could be fixed this way but not proportional stain.

lee\c

8-Jan-2007, 20:34

Having printed PMK negs for about 10 years and now going into my 4th year of Pyrocat HD I can say that:

1.the PMK negs print flatter than the Pyrocat HD negs
2.Neither PMK nor Pyrocat HD can be printed without filters on VC paper
3.Pyrocat HD is, in my system, is considerably sharper than PMK
4 Neither PMK or Pyrocat HD are grainy in 4x5 or larger which is all I use now
5.A big plus for me is that I can use rotary processing with Pyrocat HD but I can't with PMK
6.I have not had a "failure" with Pyrocat HD I cannot say the same thing about PMK
7.Much shorter development times with Pyrocat HD than with PMK

For me, the final result is "how" the image looks when printed. I use densitometers to find the film speed and the developing time (Zone I and Zone VIII) of my film. I don't care about reducing the yellow printer or whatever it is called. I am not looking for how easy the negative prints. I actually like to print. Anything else is gravy. For me, anything else outside of the 7 parameters I posted above is superficial and meaningless to me.

lee\c

Jay DeFehr

8-Jan-2007, 20:58

Hi Lee.

How do you determine film speed? Film speed is tied to negative contrast, and the printing paper's Exposure Scale. How do you determine the ES of the VC paper? What kind of densitometer do you use to read your negs? Correlating densitometry with contrast filtration and print density is at the center of my system. Regarding your parameters above, I can tell you that #1 is conditional on many factors, #2 is simply not accurate, and #s 3-7 apply only to real and/or perceived diferences between PMK and Pyrocat HD, and have nothing to do with printing on VC papers, but if you've found a process that works for you, that's all that matters.

Jay

lee\c

8-Jan-2007, 21:32

Jay,

I determine film speed using the method that Mr Adams wrote. .10 >fb+f
ES of the paper is not a consideration I use or consider relevant.
The densitometer is an Xrite color unit I borrow from a photographer close to me. I read with the blue channel. I don't know the model number it is pretty new.
Regarding #2 it is accurate as I see it and that has never been my experience with either PMK or Pyrocat HD
Since I only print on VC papers I think #'s 3 thru 7 are relevant regardless if you think so or not. Otherwise I would not have stated them.
Thank you for allowing me to have "a process that works for me".

lee\c

Jay DeFehr

8-Jan-2007, 22:21

Hi again, Lee.

I didn't mean to offend you, and I apologize if I have, I don't want to argue. My questions are sincere, and integral to the issues involved in printing stained negs with VC papers. I'm sure you know that film speed changes with contrast, and that every grade of paper is defined by its Exposure Scale, which in turn determines the negative contrast required for a full scale print at that grade/ES. This is an important issue because stained negatives act as contrast filters with VC papers, so that changes in negative contrast and/or density translate to changes in the Exposure Scale of the paper. The result is that the ES of the paper becomes an inconsistent value impossible to fix without neutralizing the contrast filtration effect of the stain (YFE) so that negative densities as read by Blue channel densitometry correlate to print densities. I didn't mean to suggest that points 3-7 are not important, just that they're not specific to VC papers, as I'm sure you'll agree. Thank you for sharing your experience, and for taking the time to consider my questions and comments.

Jay

Kirk Keyes

8-Jan-2007, 22:35

In case anyone is interested in seeing the spectral scans that Sandy refers to earlier, I did that work and I just put a graph of the data on my web site, see the following page for a link to a pdf with the graph and a short discussion of the findings:

http://www.keyesphoto.com/KDKtech%20-%20Spectral%20Scans%20of%20Pyro%20Developed%20Film.html

Kirk

Barry Wilkinson

9-Jan-2007, 08:28

Hi Kirk,

I am puzzled why you did not use the same film for the PC/PMK tests. Surely this would have given more representative results?

Barry
(Newbie at stained negs)

Kirk Keyes

9-Jan-2007, 09:17

Barry -

Purely convenience. And at the time, I had only processed a couple of runs in Pyrocat-HD.

As I said on the pdf, I did Acros and FP4+ in the Pyrocat, and they were quite similar. Guess I need to put that graph up as well...

Chuck Pere

9-Jan-2007, 10:23

JimL

9-Jan-2007, 12:46

I'm still confused about this. If you take the two film step wedges, process in the two different developers, find equal density points on the blue channel, adjust the enlarger filtration at those two points so that the light hitting the paper is neutral at that density point will the light hitting the paper also be equal at the other density points? So the color analyzer will read the same for all points on both wedges once the neutral is adjusted for the max density point. If not it would seem that the developer colors are having some effect.

I think that Jay was saying that equal blue readings of negatives at one particular density point for both of these staining developers gives equal resulting density on VC paper.

It would be interesting to see how matched blue-reading curves (matched at x no. of points or however one would best match them - I'm not an expert in this) for a film developed in the 2 developers (plus maybe a non-staining developer) translates to VC paper, and how different VC papers respond. Kirk's spectral analysis would seem to suggest there could be some difference. There's going to be some interplay between density provided by silver + stain and the changing VC filtration over the negative scale due to stain color... and it would be interesting to see this quantified with curves. This "neutral point" concept seems to be a way to establish a reference point for process control, although in the end it looks to me like VC printing the same way we've always done VC printing. Kinda like the zone system - some go to great lengths to match paper and negative scales with absolute control, some develop their own developing and printing controls with a little trial and error, and others do something in between.

The best graphical explanation I've seen of how VC papers respond to filtration is in Lambrecht and Woodhouse's book "Way Beyond Monochrome". It's also the best explanation of split filter printing I've seen.

Jim

Jay DeFehr

9-Jan-2007, 15:19

I'm still confused about this. If you take the two film step wedges, process in the two different developers, find equal density points on the blue channel, adjust the enlarger filtration at those two points so that the light hitting the paper is neutral at that density point will the light hitting the paper also be equal at the other density points? So the color analyzer will read the same for all points on both wedges once the neutral is adjusted for the max density point. If not it would seem that the developer colors are having some effect.

Hi Chuck.

Equal negative density points will produce equal paper density points, but differences in the working properties of the developers can make for mismatches in negative density points at different points on the curves. Two stepwedges developed to matching contrast that match at one density point, won't necesarily match at other density points, not becuase of the colors of the stains, but because of the working properties of the developers. The attached curves are for the same film developed to the same contrast, one in Hypercat and the other in 510-Pyro. Both negatives would print on the same grade of paper, or the same ES of VC paper, and match at at least one density point, but produce different prints. Looking at the curves, it's easy to see that the differences in the shapes of the curves will result in different prints, not because of the differences in the colors of the stains, but resulting from the different working properties of the developers. If the curves matched at every density point along their curves, the curves would be identical and produce identical VC prints excluding imaging characteristics such as grain and sharpness.

Jim,

The kind of data your suggesting is important, but beyond the scope of a thread. You're right that, in the end, printing stained negs with VC papers is similar to what some of us have always done, (much different than the method Sandy advocates) but with important differences. Most important is the ability to correlate densitometry to filtration and print density for predictable, repeatable results over the complete range of the paper's Exposure Scale. Until the combined characteristics of negatives and papers are identified and quantified, they cannot be managed effectively or used creatively.

Jay

JimL

9-Jan-2007, 18:00

The kind of data your suggesting is important, but beyond the scope of a thread. You're right that, in the end, printing stained negs with VC papers is similar to what some of us have always done, (much different than the method Sandy advocates) but with important differences. Most important is the ability to correlate densitometry to filtration and print density for predictable, repeatable results over the complete range of the paper's Exposure Scale. Until the combined characteristics of negatives and papers are identified and quantified, they cannot be managed effectively or used creatively.

Jay

Jay,

Isn't it just one step further than what you've shown here? If you take the step negatives from this plot and print them onto VC paper with filtration to match the scale of the negatives, and measure the reflection densities, then what would the 2 curves look like? By your assertion they should fit the same paper scale with the same filtration (slight difference on the shadow end), and I'm curious whether the curve shapes would maintain the same relationship to each other. Might be an interesting and relatively easy experiment (especially since I'm not the one doing it :) ). Just a thought,

Jim