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  1. #61

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    FAEW HP and FATW HP are identical in surface texture. Rivers BFK is a great paper, no doubt, but it is a printmaking paper compared to a watercolor paper which has 3 times of the sizing (so that the watercolor artist can keep moving the pigment around before it sets). In comparison of BFK to a HP WC paper there is more detail on the WC only when compared with a loupe. However when Rives BFK is married to the right subject matter it is bliss...

    With either BFK, Arches and the old but great FATW/EW/HP I always printed on the back.

    I'll definitely test FAEW/SP 300gsm and report back...

    Stan

  2. #62

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    Just to report: I used sulfamic acid at 1% to acidify some sheets of Lanaquarelle 300g/m² satin, and it worked perfectly. Dmax is significantly improved.

    I was wondering if i could also use sulfamic acid for washing cyanotypes? Normally i use citirc acid at 5%. Would i have to expect any negative effects when i switch from citric acid to sulfamic acid?
    Matthias

    Once you get born you're never the same.

  3. #63
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    Quote Originally Posted by mcilroy View Post
    Just to report: I used sulfamic acid at 1% to acidify some sheets of Lanaquarelle 300g/m² satin, and it worked perfectly. Dmax is significantly improved.

    I was wondering if i could also use sulfamic acid for washing cyanotypes? Normally i use citirc acid at 5%. Would i have to expect any negative effects when i switch from citric acid to sulfamic acid?
    Matthias,

    It is interesting to hear another %1 SA success, your choice of paper tells a lot. Lanaquarelle papers' ph is close to neutral afaik, there are various threads on Lanaquarelle on DPUG. It seems %1 sulfamic acid works with papers containing lesser the alkaline content. I haven't tried %1 SA yet, but with the papers I am working it seems impossible to me. At %10 concentration acid-base reaction takes 15mins with some papers (e.g. FAEW SP).

    If you are washing the paper thoroughly after sulfamic acid, the paper is free of acid and alkaline substances. So I would not think of any adverse effect.

    Citric acid treatment creates calcium citrate inside the paper and it is not water soluble. Not that it would have an adverse effect like oxalate crystals, but I like the idea of completely cleared paper. But as I recall many people do not wash the papers after %5 citric acid treatment. If that is your practice too, acidic paper might be problematic with certain sensitizers, for example I would expect troubles with argyrotypes.

    I am using %0,5 to 1 sulfamic acid for initial wash of modern cyanotypes. I wash the print for 30secs to 1min in SA, longer washing causes chemical fogging. I would not recommend SA for the initial wash of traditional cyanotypes due to its strong acidity. It might reduce the contrast too much and even fog the prints too fast. But it can be used for the latter clearing baths. But the papers should be washed well to remove the acid.

    Regards
    Serdar

  4. #64

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    Thanks, Serdar! I use the traditional cyanotype formula, so i will stick with a mild citric acid bath for the initial wash. I don't see fogging or a loss in contrast with concentrations up to 5%.
    Matthias

    Once you get born you're never the same.

  5. #65

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    In the meantime, I tried a few other papers in a 1% solution, and it worked fine with all of them. But I found that the key to make it work, is to give the paper a good pre soak in plain water.

    Some papers didn't show any reaction even after 20 minutes when I just dropped them directly in the SA bath. But after a pre soak of 20-30 minutes (no agitation, just dropped them in a tray with water), the reaction starts almost immediately and is done after about 5 minutes.
    The SA bath was still clearly acidic after this, so i guess even a 0.5% solution might work. But I will stick with 1%.
    Matthias

    Once you get born you're never the same.

  6. #66
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    Just to report: I used sulfamic acid at 1% to acidify some sheets of Lanaquarelle 300g/m² satin, and it worked perfectly. Dmax is significantly improved.
    I reported that as well earlier in this thread but on Rising Stonehenge.

  7. #67
    Herzeleid's Avatar
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    Can you elaborate your procedure (steps and times), paper's you have used and the process you have tried them with?

    Regards
    Serdar

  8. #68

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    Besides Lanaquarelle, I treid Arches Aquarelle 300g/m², various Hahnemühle Watercolor Papers (Britannia, Cornwall, William Turner), Bristol Paper (don't remeber the brand at the moment) and some no-name art papers i happen to have.

    1.) Pre soak in plain tap water for 20-30 minutes - depending on paper - until i felt that the paper was soaked.
    2.) 1% SA bath until bubbling/fizzing stopped (about 5 minutes), but I gave it a minute extra to be on the safe side.
    3.) Wash

    I tried Cyanotype and Van Dyke Brown with similar results. Of course the effect of the SA treatment is more pronounced with some papers, but I guess thats not a sign of incomplete acidification, but just shows that different papers have different amounts of buffer in them.
    Matthias

    Once you get born you're never the same.

  9. #69
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    Quote Originally Posted by mcilroy View Post
    Besides Lanaquarelle, I treid Arches Aquarelle 300g/m², various Hahnemühle Watercolor Papers (Britannia, Cornwall, William Turner), Bristol Paper (don't remeber the brand at the moment) and some no-name art papers i happen to have.

    1.) Pre soak in plain tap water for 20-30 minutes - depending on paper - until i felt that the paper was soaked.
    2.) 1% SA bath until bubbling/fizzing stopped (about 5 minutes), but I gave it a minute extra to be on the safe side.
    3.) Wash

    I tried Cyanotype and Van Dyke Brown with similar results. Of course the effect of the SA treatment is more pronounced with some papers, but I guess thats not a sign of incomplete acidification, but just shows that different papers have different amounts of buffer in them.
    Traditional cyanotype and VDB are not that alkaline sensitive, they are not benchmarks for determining paper's chemical purity. They would have worked without SA treatment. You might get improved results using SA. You can use %5 citric acid as well, you can wash the papers in acid until the fizzing stops, then hang them to dry (without washing) and use it for VDB. But as I said it works because those processes are not alkaline sensitive.

    Modern cyanotype, argyrotype, DOP pt/pd, ziatypes won't work with papers containing any chemical impurities. I especially test papers with modern cyanotype and argyrotype, if both works then everything else would work.

  10. #70

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    True, but i don't think that it wouldn't have worked with other processes. The SA treatment first neutralizes and then acidifies the paper, no matter if the solution is at 1%, 10% or any other concentration.

    Of course the capacity of the solution and the time it takes differ with concentration, and one has to make sure that the concentration is high enough to neutralize the buffer for a given amount of paper. But as I said, even at 1% the solution was still acidic after i treated the papers.

    I used 1 liter of the 1% solution to treat about 1800 cm² (about 290 square inches) of paper.
    Matthias

    Once you get born you're never the same.



 

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