Long Post on PdPt Exposure issues

Discussion in 'Alternative Processes' started by wilsonneal, Feb 4, 2007.

  1. wilsonneal

    wilsonneal Member

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    Please excuse the long post. If you can take the time to read it and help diagnose my frustration that would help me, and might also help others who experience similar frustration.

    I have been Pt Pd printing for a little less than a year. I had some beginner's luck, but it seems the more I learn, the less I know. The more prints I make, the harder it's getting. I'll start with a few observations of my experiences and then talk about the problems that caused me to post this.

    My first negs and first successes were with negs shot on HP5 and developed in D76 1:1. They were exposed at EI 250 and developed in rotary tubes (Beseler on a Unicolor base). The negs look a little dense to the eye, the highlights are a little blocked. On silver, this negs prints well on grade 3 to 3.5 VC. It requires a lot of burning on some of the highlight areas. In PtPd, using the NA2 method, it printed well with a coating of 18 drops FO, 15 drops Pd, and 3 drops 20% NA2. I didn't realize in those days that the NA2 should be in addition to the total drop count, and thought that it should take the place of an equal number of drops of Pd. The exposure time was about 20 minutes.

    I continued more or less in this vein until I got frustrated with extra edge density due to the agitation patterns of the Beseler tubes. During this time I shot a lot of Ilford and TMY, and saw drop counts of more or less 18/15/3 to 18/12/6 to get prints that had satisfactory contrast. I've been told this is too much NA2 and that I should work to get contrastier negatives, so I started working on that by increasing development.

    I switched to JOBO Expert drum. I also started using Pyrocat HD.

    I re-read more carefully the Weese text "New Platinum Print" and the Arentz text, and realized that my drop count was in error. I needed to ADD the NA2 count to the total drops, not replace. I corresponded with Carl Weese and he suggested that I had gone down the rabbit hole in terms of chasing contrast with NA2, leading to longer and longer exposure times. I dialed back the NA2 and saw slight reduction in print times, but with a less than acceptable contrast scale.

    My exposure times ARE quite a bit longer than my colleagues with the same equipment. Where they have 6 to 8 minutes exposures on average (with the same film, developer, exposure unit), I have times ranging from 18-35 minutes.

    In an attempt to correct this, I looked critically at all the negs. I don't have a densitometer. My thinking was that, maybe these very dense negs were a result of overexposure AND overdevelopment. I was overdeveloping to get the DR I needed for the PtPd process, but maybe my old technique of overexposing a bit (like rating HP5 at 250 for better shadow detail) from my Silver printing habits, was resulting in too much density. I began to experiment with higher EI, rating the my most recent film (J&C Classic 400) at 400.

    In these recent test, I got D76 1:1 negs that required 15 minutes UV exposure to get a decent black in the B+F area. This 15 minute exposure resulted in prints that were too dark in the Subject area. So, negs too thin. I also tried Pyrocat, and these same negs required 20+ minutes for a good black in B+F area and again resulted in a too dark print. I increased development in an effort to expand the DR. This morning I have pulled an 'acceptable' print with these parameters: J&C Classic 400 negative exposed at EI400, developed in Pyrocat 2:2:100 for 19 minutes at 72 degrees in Expert Drum on Unicolor base. Perceptions of negative--looks a little dense for Silver, but easily printable, no blocked highlights except for specular reflections. Coating was 20/20/2 drops 20% NA2, (which corresponds to Arentz 5s, the MIDDLE grade). To get an acceptable print took 37 minutes, and the B+F area is still not quite as black as areas of the print where there is PtPd coating that had no negative blocking them. Here, there's a very dense black, but in the B+F it's just near black. If I had gone for black in the B+F area, the subject would have been too dark. The print has very good contrast.

    I'm eager to resolve the issue and think I will buy a Stouffer 21 step wedge to try to get some uniformity to the tests.

    I am confused why friends with the same expo unit--a total of 8, 18-inch BLB tubes, positioned 5 inches above the contact frame--would have such wildly different times to get a respectable black in the B+F area.

    Does J&C Classic 400 have more B+F than HP5? Than TMY?

    I've never done film testing, because for my needs to date, I've been able to get close enough for Silver printing. Do I really need to pick a film and do the testing? Do I need a densitometer?

    Thanks for any thought you give this and any response.

    Neal
     
  2. Robert Hall

    Robert Hall Subscriber

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    Picking one film, doing some testing, and using a densitometer would save you some severe aggravation and save you a bundle of money in the not so long run.

    Judging from the long post, I think you kind of answered your own questions.

    Best of luck,
     
  3. donbga

    donbga Member

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    I agree with what Robert said. I prefer TMAX 400 but I can also use HP5 or FP4. Pick just one film and establish your film speed needed for palladium printing. Once you have the film speed set then dial in your processing times for the required CI.

    Pick one NA2 mixture and stick with that. If you want dual purpose negatives use that mix that produces a density range of 1.4. If you want to print on AZO, Palladium, and/or Kallitype use the 1S or 2S mixture.

    But get your results correct for palladium before you do anything else.

    The short answer is you are trying to hard and need to simplify your exposure/development steps - which are tied to your print ES.
     
  4. Ian Leake

    Ian Leake Subscriber

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    Hi Neal. I don't use NA2 so may be off, but it sounds like you're overdeveloping to me: if a similar light unit needs much less exposure time then your neg is probably too dense (though you may want to check all the UV tubes are firing up because if one or two are dead then that'll obviously have an effect - you may also be able to try your neg in someone else's unit if they're close by). Of course, their negs may be too thin...

    I'm rebelling against film testing at the moment so I'm using empirical methods. My starting point is to use the film's rated EI and N+1 development - there's usually a suggestion on the web somewhere. This get's me into the printable region. Then I refine from there. I know this isn't perfect, but it's fit for purpose.

    I've just developed my first 11x14 tonight on Bergger BPF200 which I haven't used before. The developed neg density is quite similar to an HP5 reference neg so it seems to work :smile: I'll try printing it tomorrow which should tell me how much to adjust my dev next time round.
     
  5. bobherbst

    bobherbst Member

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    I can think of two possibilities for your long exposure times. I have no experience with Pyrocat HD. Perhaps Sandy King can comment. But the combination of JOBO and pyro usually means excessive stain which can add 1-2 stops of spectral density to the negative for UV-based alternative processes. Rollo pyro was developed to address the needs of JOBO users. I have always developed in trays - 4x5, 8x10, and 12x20.

    A second variable from your friends is your contact printing frame glass. Do you know if the glass has any UV blocking elements in it? Try replacing it with a known glass type. Plexiglass passes more UV than ordinary float glass but I would never use plexiglass. Some frames are sold with it.

    An after-thought...have you calibrated your shutters to ensure your exposure is correct? I use many older Ilex shutters in my work and they must all be calibrated with a shutter tester. The marked times are never accurate.

    Bob Herbst
     
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  6. photomc

    photomc Member

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    Neal, you have already gotten very good advice from people I respect and can only add a couple of questions. Did the long print times start this winter? I wonder if your darkroom space might be too dry, and you just need to add a bit of humidity to the room. My experience has been mostly with Ziatypes (POP) and have been printing DOP palladium for less than a year. With Zia's humidity is everything, and I have found it is important with DOP as well, just not as demanding. Also, the room temp where you are printing could have an impact on how fast your negatives print as well.

    You are on the right track, IMO, by picking up a step wedge - I actually have 2 a T2115 that I use for printing (coat a small area of maybe 1x5 inches - saves paper and metal salts) and print/process as normal. The other is a model TP4x5 which I expose with the negative in camera - if you check the articles section Tim C (noseoil) did a real nice article on using a stepwedge without a denistometer.

    Considering the furstration, cost of paper and metal salts, the step wedge is well worth the money....of course that has been my experience. All of that said, it seemed like forever before I was able to get a good print, then one day it all came together (at least of a few negatives). There are still learning day (read negatives that aren't worth a darn) and good days as well.

    Good luck, and let us know how this works out.
     
  7. wilsonneal

    wilsonneal Member

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    Thanks for the feedback. Answers to a couple of questions that came up:

    Regarding shutter testing, my daylit exposures, relying on the shutter and my metering technique, have been the easier negs to print. My real troubles have been with studio flash, which of course has not much to do with shutter speed. Maybe I should just stick to working in the sun :smile:

    Regarding Humidity in the darkroom, I have a humidifier and a gauge in there. I am working in 60% RH and about 72-75 degrees.

    Think I may go back to basics: temporarily discontinue Pyriocat, discontinue J&C 400 (no loss, as we won't be able to get it easily/cheaply anymore). Will settle on HP5 in D76 1:1, get a step wedge and try to standardize more.

    Details as I have them. Thanks again.
     
  8. Allen Friday

    Allen Friday Member

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    Hi Neal,

    I use HP5 and D-76 for my 11x14 platinum work. I confess that it is my least favorite film for platinum, but I use it because I have a lot of the film. Once it is gone, I will shift to J&C 400, which I use in 16x20 and 20x24 or fp4.

    The problem with HP5 is that it is a push film, not really an expansion film. As I extend development, the shadows also increase in density. This leads to longer print times and I have to use a more contrasty mixture of Pt/pl.

    I develop HP5 in d76 1+0 for 12.5 minutes in a jobo processor for N development. I then selenium intensify the negative in toner 1+1 for 5 minutes. The combination of developer and intensification will get the negative up to a DR of 1.6 to 1.7. The Arentz book, at least the latest edition calls for D76 1+0 for 11 minutes at EI 400 for a DR of 1.6. Or, D76 at 1+1 for 17 minutes at EI 400. Frankly, I have never had much luck with d76 at 1+1 with HP5. My times were based on my own BTZS testing.

    Print times for the HP5 are longer than for the J&C or Tri-X. My print times with this film are around 15 minutes. The film works better in pyro, but I am not a big fan of working with pyro, especially in a jobo.

    I would really recommend doing an organized film and paper test for your working method and materials. Either BTZS or ZS. It will save a lot of frustration in the long run.
     
  9. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    Neal- from reading your description, even assuming the J&C at 400 instead of a lower ASA, it sounds to me like you're nuking the hell out of your film. In my Jobo, I'm dealing with 11-13 minutes for HP5+ in Pyrocat, 1:1:100, not 2:2:100, rating my HP5 at 200. Also, if your negs are truly contrasty, they should be printing on a LOWER grade of silver, not higher. I think your negs are just way too dense across the range. Can you throw one on a lightbox and shoot a digital pic of it so we can get an idea of what it looks like in general?
     
  10. wilsonneal

    wilsonneal Member

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    Yes, I can do that photo on a light box. And you may be right. But if you are, the troubling thing is Why, with a neg that looks so thin to the eye, does it take 15-18 minutes to get B+F to go black? I'll pull out a light box tonight after work.
    Thanks,
    N
     
  11. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    You're saying your negs look THIN when you're cooking them that long in the soup? I think you may have other issues then, but let's see your negs first. What you think is thin and what I think is thin may be two different animals. Or you may have some other issue that is causing an excess of base+fog density (some kind of UV blocker in the film??? who knows...)
     
  12. Kerik

    Kerik Member

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    Just a few quick thoughts:

    -First, I disagree with Don regarding the Na2 mix. For in-camera negs, trying to standardize on one contrast mix will just drive you nuts. To me, the purpose of Na2 is the ability to adjust your contrast mix, not standardize on one. With digital negs, it's a different story since it is much easier to make them virtually identical in DR.

    -Three drops of 20% Na2 in an 8x10 print is a LOT, as I think you've discovered.

    - For HP5+, I highly recommend Rollo Pyro in trays. I rate it at 160 and develop for about 8 or 9 minutes at 70 degrees with more or less continuous agitation. With this combination I am able get very good results with HP5 without the need to pump in a lot of Na2. I had much poorer results with PMK and Pyrocat HD. I use a UV box with 4-foot 40 watt tubes and my exposure times are usually in the 6 to 9 minute range. Let me add that I typically only use HP5+ for "normal" lighting conditions. For low contrast, soft light FP4 or TMY are much better choices.

    Hope that helps a bit...
     
  13. wilsonneal

    wilsonneal Member

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    Kerik:
    Thanks, but wait. Here's my disconnect. If you look at Arentz's chart here: http://www.dickarentz.com/na2.html
    you can see that for a 1.4DR neg (like, close to IDEAL for PtPd and he even calls it "Medium"), he specs 1 drop of 20% for a 4x5. 6 drops FO, 6 drops PD, 1 drop 20% NA. That would equal 4 drops 20% NA for an 8x10, right? My understanding of Arentz is that he's specifying 12 drops for a 4x5 and 48 total drops for an 8x10?

    So based on that, 3 drops of 20% NA2 is about right for a the middle of the scale? Or is there another way to interpret this chart, which is the basis for my method.

    Thanks.
    Neal
     
  14. Kerik

    Kerik Member

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    Wilson,

    Hmmm... Well, let me put it this way. I was a "Beta tester" of Na2 for B&S when Dick Sullivan first stumbled onto its properties several years ago. So, I have not adopted Arentz' approach (which for my way of working is way too complicated). I've been platinum printing long enough (17+ years) that I prefer to work much more intuitively. I don't use a densitometer (although I actually aquired one recently but I've yet to use it). I prefer very warm prints, therefore I want to use pure palladium with little or no Platinum (Na2 or otherwise). I process my negs so they will print well with either no Na2 or just a bit. I think the most I've used is 6 drops in a 14x17 print (which is roughly equivalent to 2 drops in an 8x10).

    So, while 4 drops may be Arentz' middle range, it's off the scale for how I work. I'm not saying Arentz is wrong, he's absolutely one of the best pt/pd printers around, he just takes a different, more analytical approach where I prefer to fly by the seat of my pants and rely on my own experience. This ain't rocket science, and I should know since I work for a rocket manufacturing company in my "spare time". :smile:
     
  15. sanking

    sanking Member

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    Long exposure times with any staining developer are almost always the result of over-exposure. The plain and simple fact of the matter is that stain is proportional to silver density, and exposure with any process is based on shadow density, where there is very little stain. If you measure the shadow density at Zone III of correctly exposed stained and non-stained negatives there should be little difference, certainly no more than about + log 0.10 for the stained negative. And that is about what I see in my own work, i.e. correctly exposed stained negatives required about 1/3, or at most 1/2 stop more exposure non-stained negatives.

    Unfortunately much of the literature on pt/pd printing suggsts that we need to make very strong negatives for the process, and many people wind up giving more exposure than is needed. In my own work I find that when developing for the high contrast needed for alternative printing an EFS of about 2X the maker's rating is required to avoid over-exposure. For example, I generally rate TMY at EFS 600, or even 1200 when exposures are based on incident readings in the shadows as in BTZS procedure.

    Another issue with staining developes is B+F. All of the staining developers will develop more B+F or general stain (which adds to printing time) with constant rotary agitation (say in tubes or in Jobo) than with tray agitation. For that reason many good pt./pd printers who use Pyrocat-HD, Tillman Crane for example, develop in trays. I develop some ULF film with rotary develoment in tubes with Pyrocat-MC, which contains ascorbic acid, because this developer gives a lower B+F with long develoment than Pyrocat-HD. However, whenever practical I develop in tubes with minimal agitation procedures, which gives the lowest B+F stain of any method with staining developers.

    Sandy King
     
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