double-coating pt/pd

Discussion in 'Alternative Processes' started by TheFlyingCamera, Sep 6, 2010.

  1. TheFlyingCamera

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    I did my first double-coated pt/pd print today. I had an image that really begs for the cool platinum image tone much more than the warm palladium, so I first tried a pure platinum print. That was a failure - really underexposed (my fault) and it looked really thin - I'm guessing too low a drop count. Re-did it with an 80/20 Platinum/Palladium mix and a higher total volume of solution. Better, got the exposure about right, but the contrast was still off. So I decided to try a double-coated print, as it's supposed to yield better contrast. It definitely worked. I was able to see far more detail in my shadows than I was before, and the blacks are snappier. Now the decision is, is it worth it?
     
  2. keithwms

    keithwms Member

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    In my estimation no, it wasn't worth it for me, although maybe when I see your print I'll think otherwise! Anyway, maybe once I get over my move and unpack my roomful of boxes of photo stuff I'll get back to the project of adapting an inkjet to apply Pt/Pd solutions. Then multilayering might be reasonably economical.

    I've read about applying gum over platinum for better depth, have you tried that yet? I applied sandarac varnish and that helped a fair amount.
     
  3. phaedrus

    phaedrus Member

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    Not to diminish or discourage your efforts, but would that work even theoretically? Has it been done? Aren't the print head's orifices metallic and heated? Wouldn't they clog with metallic Pt and Pd right away?
     
  4. Ian Leake

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    Congratulations Scott. Double coating can be a PITA and the difficulty / benefit depends on the paper, but when you've found a way that works it can really lift a print.

    Was it worth it? That depends on whether the print looks better than when single coated. I've made double coated prints which zing from across the room, and others which are not much different from a heavy single coat.

    Enjoy the new tool in your tool bag.
     
  5. donbga

    donbga Member

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    Yeah right. That will be the day that frogs can fly.:smile:
     
  6. donbga

    donbga Member

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    Have you tried printing pure platinum prints that are brush developed in glycerin and potassium oxalate? This procedure is described in Sullivan & Weese's New Platinum Print. The method works very well. However it's a bit too expensive for my wallet, I've only made 3 pure platinum prints with that technique.
     
  7. Ian Leake

    Ian Leake Subscriber

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    From your description this sounds like how the early platinotype printers used to control contrast. Developer temperature effects development time. By using a cool developer with glycerin on the print and in the developer they could really slow down the development time which allowed them to control local contrast with a brush. It's very effective, although for most purposes it's easier to use a dash of potassium dichromate coupled with some judicious dodging and burning.
     
  8. TheFlyingCamera

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    The double-coat in this case was definitely effective at snapping up the Dmax and improving mid-tone contrast, at the sacrifice of my highlights. All I need to do in this case now is to bring the highlights up back to near-white. I tried doing a pure platinum print but that didn't work very well - I used the same drop count I would have used for a palladium, and at the same time as my palladium print, it looked like it was about 2 stops underexposed and needed about double the coating solution - you could see brush marks in the image area. I'm using Bergger COT320 for my paper so I doubt it's a paper issue.
     
  9. Ian Leake

    Ian Leake Subscriber

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    COT320 isn't a good paper for pure platinum prints. The gelatin sizing binds to the potassium chloroplatinite and hinders the chain of reactions which forms the image. Try printing on the reverse side where there's no gelatin. As far as I'm aware there's only one paper which works for a pure platinum image 'out of the box' and that's Buxton.
     
  10. Davec101

    Davec101 Member

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    Did you take a density reading of the double coated print? We have been discussing related issues over at the hybrid forum at length, here : http://www.hybridphoto.com/forums/showthread.php?t=2047

    I will be testing Penn's method of double coating on sheets of paper bonded to aluminium in the next couple of weeks to see if their is a significant difference using a platinum/palladium mix.
     
  11. jeffreyg

    jeffreyg Subscriber

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    Everyone has their own recipe for emulsions. I for one haven't tried double coating but I have found the Bergger COT320 to be more iffy to work with. The Arches Platine is more compatible with my technique. For what it is worth I find 0.5cc of emulsion is enough for a 4x5 and 1.3cc for an 8x10. I use pipettes - accurate to 0.1 ml to measure each solution and a syringe to spread the emulsion to a puddle pusher. For some negatives I might alter the emulsion but that's usually for contrast control. I prefer pt/pd with a tiny amount of gold chloride over single elements but to each his own.

    http://jeffreyglasser.com/
     
  12. TheFlyingCamera

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    I don't have a densitometer at home with which to take readings, so I'm just going by eyeball.
     
  13. TheFlyingCamera

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    What would I have to do to other papers to make them ready? Oxalic Acid pre-bath? or something else?
     
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  15. Ian Leake

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    The honest answer is that I don't know for certain what pre-treatment is required for other papers. I only use Buxton for pure Pt.

    I believe that acid treatment is the secret. I've heard that the first Pt coat may be sufficient to acidity the paper for the second coat. But I've not actually tested this.
     
  16. donbga

    donbga Member

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    Not so by my experience, Platine worked fine.
     
  17. donbga

    donbga Member

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    Yes you are correct that was a technique used to control different contrasts in a print.
     
  18. donbga

    donbga Member

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    If you have a flat bed scanner and the pro copy of Vuescan that supports the scanner you can use that combination to read reflection densities. I would be surprised if you have DMAX readings much above log 1.4 to 1.5. But I think it's sort of foolish to get into this numbers debate, if your "blacks" look black enough then that's all that really matters.
     
  19. Ian Leake

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    Interesting. I only managed to get gritty, dirty, partial images. We must be doing something different (or maybe my paper was dodgy). I may try Platine again. Thanks.
     
  20. TheFlyingCamera

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    I'm going to start with Platine as an alternate paper first - in the US, Buxton is ungodly expensive - I can buy a 30x44 inch sheet of Platine for half of what a sheet of 22x30 Buxton costs. Which, if you really want to use it, can be bought from Talas Online.
     
  21. jeffreyg

    jeffreyg Subscriber

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    I don't pretreat Platine. Once Bostick and Sullivan stopped carrying Crane's Platinotype I tried a number of papers but have worked best with Platine. It has a nice natural color, coats easily and has good wet strength. I found that when using a puddle pusher it is best to have a piece of matte board under the paper rather than having the paper directly on a hard surface. I also let the emulsion soak in for about five minutes before drying it.
     
  22. TheFlyingCamera

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    Jeff- are you doing palladium, platinum/palladium blend, or pure platinum prints?
     
  23. jeffreyg

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    Platinum/palladium + a very small amt. of gold-chloride. I am using HP5 film in 4x5 and Delta 400 in 6x6. The 6x6 I enlarge on to x-ray duplicating film which is extremely slow but is a terrific reversal film. I will also enlarge the 4x5's the same way. I have made successful digital negatives from scanned film but while I have made very good prints from them they still don't match the duplicating film.

    http://jeffreyglasser.com/
     
  24. cowanw

    cowanw Member

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    I am hesitant to say this as I am very new to this,so, at the risk of looking stupid. I did read once that Colburn coated both sides of the paper and that Stieglitz was very impressed with the dmax that resulted. As a historical reference this might be worth looking at (or not)
     
  25. michaelbsc

    michaelbsc Member

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    What X-ray duplicating film are you using if I may ask? And can you give us a supplier?
     
  26. Davec101

    Davec101 Member

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    Where did you read this? it sounds rather odd, but interesting all the same :smile: