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  1. #11

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    Ha, weird...I routinly leave my prints for 15 minutes per bath for a total of 45 in HCA and have never noticed this. I think I am going to print a step wedge and check it out, it might be the reason I only get a Dmax of about 1.35.....live and learn!

  2. #12
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    Newbie here, but I understand the palladium is more sensitive to HCA bleaching than platinum.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  3. #13
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    No doubt that insufficient clearing is a much bigger problem than bleaching from HCA.

    And there is also no doubt that it is paper dependent. Doubters should try clearing double-coated Rives BFK sometime!

    Your point is correct - you just have to keep an eye on things and check clearing occasionally by masking your borders (or some area on the coated area of your print) I have seen a number of prints with 'show the brushstrokes' borders that probably are not completely cleared.



    Quote Originally Posted by Kerik
    Problem is, this isn't easily defined since it will be different for different papers and for different temps, etc. Too little clearing will be worse in the long run. I've never noticed any bleaching from HCA, although I've never left a print in for 30+ minutes. No one ever calls me...

  4. #14

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    Quote Originally Posted by clay
    Another thing I forgot to ask is if you mix in some oxalic acid with your ferric oxalate when you mix it into solution. It really helps promote clearing, plus speeds up your printing times by nearly a stop (My experience is that 4g oxalic/27g ferric oxalate/ in 100ml of water will make printing times about 60% of what they would be with ferric oxalate used alone)
    Sorry for the delayed reply. I'm loosing a little sleep over this one. I got the kit from B&S, so I don't suppose there's oxalic acid in the bottle of ferric oxalate. Think I should purchase some and have it handy. Your question led me to investigate the New Platinum Book and I found that I can add EDTA Tetrasodium too. If yes, question is:

    1. Is EDTA Tetrasodium similiar to the Edta Clearing Agent B&S sent me?

    2. Is it okay now to add Edta to the already mix ferric Oxalate?

    3. Does Oxalic acid do a better job than Edta added to Ferric Oxalate solution?

    Next... Hope this isn't a dumb question, but does it make sense to alter the pH of the rinse/wash water by adding a little of "something" to it?

    I've got a nice print made a few days ago and I'm 100% sure it hasn't been cleared sufficiently. The print border isn't masked. With all the soaking in pH positive rinse/water baths, will it retard clearing action if I did re-clearing, following the procedure as you described earlier?

    Thanks again for being so helpful.

  5. #15

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    Quote Originally Posted by colrehogan
    Clay, have you tried using 7-Up for a source of phosphoric acid?
    Actually I did looked at the content of Sprite can, and it said citric acid. Maybe I'll check 7-up. Thanks!

  6. #16

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    Quote Originally Posted by avandesande
    Muriatic acid and sulfuric acid will eat up your pipes.

    Phosphoric acid is much safer to handle and for your plumbing. I would try a pool store, i think the 'ph-down' type products are phosphoric acid.
    Also look in a hardware store for 'naval jelly', same thing.
    Just make sure to read the label to see if there are any undesirable additives.
    Good resource avandesande. Thanks to you too.

  7. #17
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    Quote Originally Posted by eggshell
    Sorry for the delayed reply. I'm loosing a little sleep over this one. I got the kit from B&S, so I don't suppose there's oxalic acid in the bottle of ferric oxalate. Think I should purchase some and have it handy. Your question led me to investigate the New Platinum Book and I found that I can add EDTA Tetrasodium too. If yes, question is:

    1. Is EDTA Tetrasodium similiar to the Edta Clearing Agent B&S sent me?

    2. Is it okay now to add Edta to the already mix ferric Oxalate?

    3. Does Oxalic acid do a better job than Edta added to Ferric Oxalate solution?

    Next... Hope this isn't a dumb question, but does it make sense to alter the pH of the rinse/wash water by adding a little of "something" to it?

    I've got a nice print made a few days ago and I'm 100% sure it hasn't been cleared sufficiently. The print border isn't masked. With all the soaking in pH positive rinse/water baths, will it retard clearing action if I did re-clearing, following the procedure as you described earlier?

    Thanks again for being so helpful.
    Answers:
    1.Yes.
    2.Yes, but probably not necessary.
    3.The EDTA seems to help the ferric go into solution, so adding it later won't do much. It's the oxalic acid that seems to help with printing speed and clearing.
    Next...yes, you could sprinkle some oxalic or citric acid into your rinse. Or, just follow the clearing process as Clay described.
    Finally, you can go ahead and re-clear the print starting with step 3. in the procedure that Clay outlined above. Did you tell us what paper this print is on?
    Kerik Kouklis
    Platinum/Gum/Collodion
    www.kerik.com
    2014 Workshop Schedule Online

  8. #18

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    Quote Originally Posted by Kerik
    Answers:
    1.Yes.
    2.Yes, but probably not necessary.
    3.The EDTA seems to help the ferric go into solution, so adding it later won't do much. It's the oxalic acid that seems to help with printing speed and clearing.
    Next...yes, you could sprinkle some oxalic or citric acid into your rinse. Or, just follow the clearing process as Clay described.
    Finally, you can go ahead and re-clear the print starting with step 3. in the procedure that Clay outlined above. Did you tell us what paper this print is on?
    Thanks for the answers, Kerik. Really appreciate it! The print I need to re-clear is made on Platinotype paper. I will try to re-clear the print using those steps but there's no way of telling if it clears completely since the border wasn't masked.

    Now for the good news. I double-coated two strips (full strength & half strength), one on platinotype, the other, Cranes Kid Finish paper. After drying, I immersed the two unexposed strips into the usual Pot. Ox. developer. Removed the strips after 5 min. Some stains could be seen. They went immediately into 1st HCA/Edta bath. Within 3 min. the stains are completely gone. It worked! Lesson learnt!!

    Thank you very, very much Clay. I wouldn't know how to fix the problem without asking for help. Newbies like me can really benefit from you, Kerik, Jorge and others. I am humbled by your experiences.

    Thanks to all.

  9. #19

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    Oh yeah, I forgot to mention the strip went into citric acid bath before 1st HCA/Edta bath. There was still a faint stain after citric acid bath, and cleared completed within 3 min. in HCA/Edta bath.

    I'd glad I need not have to handle stronger acids. Thanks again.

  10. #20
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    The only reason we know any of this stuff is because we were humbled by experience! In alt process stuff, just like most things in life, the moment you think you have it figured out, the flying spaghetti monster intervenes and makes you feel like a fool.

    http://www.venganza.org/

    Quote Originally Posted by eggshell
    I am humbled by your experiences.

    Thanks to all.

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