Exposing/developing for Azo/Platinum

Discussion in 'B&W: Film, Paper, Chemistry' started by ImageMakers, Apr 22, 2005.

  1. ImageMakers

    ImageMakers Member

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    Hello- I will be making my first attemp at Azo and Platinum and do have a couple questions.

    1.) Is there a general number of stops to over expose the negative?

    2.) Percentage of over-development, if neccessary?

    3.) Will the negative work with both processes? I understand both prefer a dense negative.

    I will be experimenting with Efke 100 4x5 sheet film and Pyro developer.

    Thanks,
    Jim
     
  2. Daniel Grenier

    Daniel Grenier Member

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  3. Donald Miller

    Donald Miller Member

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    There continues to be a misconception about the negative characteristics required for an Azo negative. In response to your questions:

    1. You don't need to over expose a negative for use with Azo...in fact it may prove counterproductive since it may very well reduce the density range that the negative will exhibit. Depending on the subject matter and the inherent scene contrast you may actually effectively underexpose because the EI of the film is not a fixed factor. The EI will actually increase with increased development.

    2. Yes you do need to increase development...How much? depends on the film and a number of other factors including developer, and method of development...the best thing to do is do the testing yourself.

    3. Yes the negative will work with both processes...but again I reiterate...Azo does not require a dense negative it does instead require a negative with a high density range...or contrast. Typically this will be on the order of 1.65 for grade two Azo. This is not a Zone VIII density measurement. It is instead a measurement where the low value density is subtracted from the high value density.
     
  4. ImageMakers

    ImageMakers Member

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    Thanks for the input. I will most likely shoot the same scene multiple times, then develop each different and see the results and take it from there.

    -Jim
     
  5. Donald Miller

    Donald Miller Member

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    In my process I use tube development with minimal agitation using Pyrocat HD at 1-1-150 dilution. For Efke PL 100, the times for SBR 5 1/2 are 60 minutes. For SBR 6 is 47 minutes. For SBR 7 is 38 minutes.

    Tray development at 2-2-100 with Pyrocat HD would be different.

    Development with rotary development would be different again.

    Development with ABC Pyro could be different again.

    I would not be prone to recommend a given time without knowing the developer choice and the agitation procedure. That would not be an intellilgent thing to do.
     
  6. Jorge

    Jorge Inactive

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    And the given subject contrast. Where I live is semi desertic, I develop TMY in tubes for 4 min in pyrocat HD 2:2:100 at 76 ºF for a subject with a measured SBR of 11.
     
  7. matt miller

    matt miller Subscriber

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    4 minutes? that's great. I'm using trays & see times around 12-17 minutes. I can't stand it. I'd love to get it down to 4 minutes. Maybe I should pull the tubes back out, increase the temp & give it another go. 4 minutes of spinning tubes sounds a heck of a lot better than 17 shuffling sheets.
     
  8. Jorge

    Jorge Inactive

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    Dont get too exited, my developing times for SBR of 4 is 22 minutes..... I agree, it is the pits to stand there rolling for this long.
     
  9. ImageMakers

    ImageMakers Member

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    Great info so far, much appreciated. I checked B&H's website and see multiple choices for Pyro. Can someone recommend which to start with? I will be tray processing first, then setting up a Jobo later.

    Thanks - Jim
     
  10. noseoil

    noseoil Member

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    After trying PMK, ABC and finally Pyrocat, save yourself some trouble and just use Pyrocat with tubes. You will have great results and the lights can stay on for most of the time.

    I've used it with Efke 25 and Efke 100 and am pleased with results. tim
     
  11. Donald Miller

    Donald Miller Member

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    While I have seen some excellent prints from PMK, ABC and Pyrocat. I don't like the first two I mentioned in my work. My preference in the order of preference are 1.Pyrocat, 2. ABC, 3. PMK.

    The thing that would influence my decision, were I in your position, would be the characteristics of these developers as they affect UV transmission for your planned Pt-pd printing. Pyrocat will give you better performance in that situation.
     
  12. c6h6o3

    c6h6o3 Member

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    Try this - should prove to be easiest for you - especially since you want to do both tray and rotary processing.
     
  13. donbga

    donbga Member

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    A Donald Miller has pointed out there is no need to "overexpose" for AZO or palladium prints.

    One thing that I will point out is the latest version of grade 2 AZO has a much longer exposure scale that previous versions which makes it difficult to build a negative that will print well with palladium and AZO, so you may wish to calibrate on grade 3 instead and then use a contrastier developer for palladium prints.

    Also the new grade 2 by my tests is about 2 stops slower than the older emulsion versions and there is no guarantee that Kodak won't change something in the future.

    I've used PMK, ABC, and Pyrocat developers with success but Pyrocat is my preferred developer of the three. With a staining developer you have a better chance of making a multi-process negative.

    If you are just starting out with both AZO and palladium I would reccomend that you master AZO first and not worry about the other. Mixing your own developer is the most economical way to go, paying for some else's water isn't economical.

    Good luck,

    Don Bryant
     
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  15. sanking

    sanking Member

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    I am going to propose something that has not been mentioned before, at least so far as I know. We all are aware of the fact that AZO is *very* sensitive to UV light so why not take advantage of a pyro negatives stain, which functions as a highly actinic filter to UV light, to increase the effective printing contrast of AZO. All we would need to do is substitute the typical R40 floodlight that is used for printing with AZO with a bulb that puts out a lot of UV light. Given the fact that AZO is much more sensitive than alternative processes the bulb could be fairly low in wattage. I have already printed AZO #2 with a plate burner (NuArc 26-1K) and know for a fact that the UV light gives more contrast. Unfortunately, exposures on AZO are so extremely short with plate burners as to be impractical, but one could use other less powerful sources, say one of the 150 watt mercury vapor yard lights placed 6-8 feet from the printing frame.

    The use of a UV light source in printing AZO would, in principle, allow us to make dual-purpose pyro negatives that would print equally well on a high ES process such as palladium as well as AZO #2.

    Sandy
     
  16. Donald Miller

    Donald Miller Member

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    Sandy, I would agree with your thoughts on this. About a year ago, I did some testing with the F15 T8 Blb lamp on negatives exposed to Azo. These were negatives that were developed in Pyrocat. My results indicated that this is a much more effective way to expose Azo. The times were reduced by approximately 1/2, as I recall, when compared to the 300 watt R 40 lamp. My tests were conducted using one of the aforementioned lamps at a height of 17 inches above the printing frame. I too found that contrast increased when using a purer UV lamp.

    I would think that the 150 watt mercury vapor lamp would still produce printing times too short for effective dodging. My thinking is that the lower wattager lamps would be better for this.
     
  17. sanking

    sanking Member

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    Donald,

    You could be right about the 150 watt bulb. As I recall my exposures with the NuArc 26-1k on AZO #2 were on the order of 0.5 units, or less than a second.

    BTW, I repeated my post on the AZO forum so you might want to join any subsequent discussion on this issues there as well.

    Sandy
     
  18. Donald Miller

    Donald Miller Member

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    Thanks Sandy I will check into it...
     
  19. ImageMakers

    ImageMakers Member

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    To Jorge- You mentioned developing tubes. Is this for rotary processing or manual? Again...Thanks for the input. I will begin experimenting within a few weeks and will post results. - Jim
     
  20. Jorge

    Jorge Inactive

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    Very manual, you have to stand there rolling the tubes. I got the ones JandC is selling...try them, they are great and cheap... :smile:
     
  21. sanking

    sanking Member

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    Just a clarification of terminolgy. Developing in tubes can be done with either stand or semi-stand type of agitation, where one would stand the tubes on end and fill them with developer, or with rotary processing, using a small amount of developr and agitation by rolling the tubes around.

    The term rotary means that agitation is done by rolling the tubes around, and this could be done either manually (as we do with BTZS type tubes,. where we typically roll the tubes around in a water bath) or by the use of a motor base, as with Jobo or as we might do in developing film in print drums.

    Sandy
     
  22. doughowk

    doughowk Subscriber

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    I got tired of rolling my home-made tubes in a tub. Bought a used Unitron motor base on eBay, but my grey conduit tubes wouldn't rotate (too small). So, made a sling for each end of tube, and suspend the tube above the motor base. Works fine & don't have to worry about tubes 'walking off' the motor base.
     
  23. Kirk Keyes

    Kirk Keyes Member

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    Sandy - this also leads to the idea that one could, if one can find a set of lights/lamps with a good balance of intensity, make a variable contrast printing setup for the Azo paper.

    Instead of the usual VC setup of using a set of filters with a single lamp, use two lamps for different times or intensity settings. Exactly like the way VC cold light heads work.

    Once the lights are getting close in printing time/speed, it may be possible to make fine adjustments to the overall balance of the lights though filtration. They could be permanently filtered, and then contrast could be adjusted simply by time.

    Kirk - www.keyesphoto.com
     
  24. Donald Miller

    Donald Miller Member

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    I would be very surprised if this would work. The VC materials have two emulsions whereas Azo is a single emulsion material. In other words it either exposes or it doesn't...

    The degree of variation from two light sources to expose Azo through a stained negative are best accomplished with other means. For instance Amidol with water bath would be far more effective to decrease contrast. It is virtually impossible to increase a papers exposure scale past the emulsion characteristics.
     
  25. Kirk Keyes

    Kirk Keyes Member

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    Well, you might be surprised, but Sandy has said that he can get two different contrasts out of the Azo by using different light sources. I'm taking his word on that observation. So it only goes to follow that if one varied the light sources, one could control the contrast range of the paper. We don't have to change the contrast of the paper at all, since we are controlling the contrast with the filtration that is inherent in the stained negative.

    And yes, VC paper's have two emulsions, each with different intrinsic contrasts. In fact, Ilford MG IV claims to have 3 emulsions to accomplish the VC properties.

    Sandy's measurements have shown that the PyroCat density increases with decreasing wavelength, i.e. PyroCat has a much greater density in the UV than in the blue or green wavelengths. That density probably increases fairly continuously as the wavelength decreases. Combine this with the spectral characteristic of the Azo paper, and that is what would give us the VC properties of this technique. See this for the spectral properties of Azo. http://www.kodak.com/global/en/professional/support/techPubs/g10/f009_0106ac.gif
    So we accomplish this either of two ways here -

    1) Pick a light source that is "tunable" so that we can vary the wavelength of the light that goes through the negative, and the negative will have a different contrast range based on the wavelength we "tune" to, or

    2) Vary the amount if light coming from each end of the spectral sensitivity spectrum of the Azo paper. By changing the ratio of these colors of light, we would be making 2 exposures on to the same paper with a negative that had 2 different "contrasts". The combination of those exposures, when properly balanced, could create an exposure of either contrast extreme, or somewhere in the middle.

    I'm not saying it would be easy to do, but it should work...

    You may be right, water baths may work better. But then how do you increase the contrast with a water bath?

    Donald, I don't mean to say there aren't better ways to control the contrast, I'm just pointing out that here's another way that probably hasn't been tried yet.
     
  26. Donald Miller

    Donald Miller Member

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    Kirk Keyes wrote :

    "You may be right, water baths may work better. But then how do you increase the contrast with a water bath?"

    Kirk,

    Apparently you failed to read what I wrote earlier in which I stated that it is virtually impossible to increase the contrast of a fixed grade photographic paper beyond the emulsion characteristics. The only reasons that uv light increases contrast with Azo is that Azo is quite sensitive to this portion of the spectrum and also because of the actinic quality of Pyrocat stain. If one used a non staining developer in lieu of pyrocat then there would be no difference in the contrast of Azo between uv lamps and the conventional floods that most of us use.

    By the way, I visited your website...It seems that most of your work is in color which is very nice. However I saw only two images portrayed as black and white. Do you have additional black and white images? Do you use Pyrocat developer? Do you contact print on Azo? Have you ever used this material?