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  1. #11
    Barry S's Avatar
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    For large amounts of cyanotype sensitizer, it doesn't make any sense to buy prepared kits. Classic cyanotype sensitizer uses stock solutions that combine to yield 10% ferric ammonium citrate and 4% potassium ferricyanide. If you buy these easily obtainable chems, the cost is about $7.50/liter here.

  2. #12
    Vaughn's Avatar
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    The prices I worked out for the traditional cyanotype were B&S prices for the Ferric Ammonium citrate and the Potassium ferricyanide. If you can order and ship the chemicals from them (unless you can find a more local chemical supplier), you will need 200grams of the Ferric Ammonium citrate (add to 1 liter water) and 80grams of Potassium ferricyanide (add to 1 liter of water) -- and you will have your 2 liters total. The 200grams of ferric Ammonium citrate is US$19 and 100 grams of Potassium ferricyanide is US$7.00.

    If you don't have a way to weigh out the chemicals, B&S would probably package up 80 grams of the Pot. ferricyanide for you...they are good about that sort of thing.

    Vaughn

    PS...as Barry shows in his post, there are a variety of receipes. Part A in his is 10%, mine above is 20% and I have read another one at 25%. His Part B is 4%, mine is 8% and the other I read was 10%. Whatever works!
    Last edited by Vaughn; 02-19-2009 at 08:55 AM. Click to view previous post history.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  3. #13
    Davec101's Avatar
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    Quote Originally Posted by Vaughn View Post
    The prices I worked out for the traditional cyanotype were B&S prices for the Ferric Ammonium citrate and the Potassium ferricyanide. If you can order and ship the chemicals from them (unless you can find a more local chemical supplier), you will need 200grams of the Ferric Ammonium citrate (add to 1 liter water) and 80grams of Potassium ferricyanide (add to 1 liter of water) -- and you will have your 2 liters total. The 200grams of ferric Ammonium citrate is US$19 and 100 grams of Potassium ferricyanide is US$7.00.

    If you don't have a way to weigh out the chemicals, B&S would probably package up 80 grams of the Pot. ferricyanide for you...they are good about that sort of thing.

    Vaughn

    PS...as Barry shows in his post, there are a variety of receipes. Part A in his is 10%, mine above is 20% and I have read another one at 25%. His Part B is 4%, mine is 8% and the other I read was 10%. Whatever works!
    Thanks Vaughn for your post, thats just the kind of info i need, i think float coating would be a good idea to try for 30x24" and above, i imagine one would have to avoid getting sensitiser on the other side of the paper and it would probably require 2 to 3 'floats' in the sensitiser bath. Two litres would am sure be more than fine and at those sort of prices i would definatly give it a try even if its just to practice. What type of blues are you getting with Classic Cyanotype? are they are as deep and rich as the modern version?, my initial tests with the classic formula some time ago yielded quite dull blues and so i switched to the modern.
    Last edited by Davec101; 02-19-2009 at 10:07 AM. Click to view previous post history.
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  4. #14
    Barry S's Avatar
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    Quote Originally Posted by Vaughn View Post
    ...

    PS...as Barry shows in his post, there are a variety of receipes. Part A in his is 10%, mine above is 20% and I have read another one at 25%. His Part B is 4%, mine is 8% and the other I read was 10%. Whatever works!
    Sorry if I wasn't clear, but I was giving the final concentrations in the combined sensitizer to show how much chemical is needed per liter. The individual A and B stock solutions are 2X, so that's the same as your 20%/8%.

  5. #15
    Jim Noel's Avatar
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    Beware of airbrushing. You don't want to be breathing the fine mist of the sensitizers. Wear something better than a dust or painting mask.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

  6. #16
    Barry S's Avatar
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    Quote Originally Posted by Jim Noel View Post
    Beware of airbrushing. You don't want to be breathing the fine mist of the sensitizers. Wear something better than a dust or painting mask.
    I agree. Aerosolizing the sensitizer would be my last choice for safety reasons. Not that it's particularly nasty, but be kind to your lungs. Considering how inexpensive the sensitizer is if you mix it yourself, I'd just use a trough to coat the sheets.

  7. #17
    Vaughn's Avatar
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    Dave, I have gotten some intense blues...double coating helps, and intensifying in an Ammonium dichromate bath can help, too. (Cyanotype II uses Ammonium dichromate in the formula, as well as Oxalic acid). The paper plays a big role, too. Buffered paper ("acid-free") interfers with the process. With platinum printing I use a 5% Oxalic acid bath to acidify the paper for better results -- while I have not done this with cyanotypes, it probably would help when using alkaline papers. I am not a cyanotype expert -- I have made them, and have taught others to make them in classes, but others might have more intense knowledge about the process.

    Multiple float-coats should do the job -- letting the coats air dry between coats. Using a hair drier might be difficult on such a large sheet of paper -- uneven drying might result in uneven second coats.

    Jim brought up a good point...if I were to airbrush, I would actually construct a make-shift fume hood to insure that I would not be breathing the mist. I make a small one when I use acetone for sensitizing my carbon tissue...breathing acetone just ain't my thing...LOL!

    Thanks for the clarification, Barry...I did not read your post carefully enough.

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  8. #18

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    Allan Jenkins

    Hi Dave

    I assume you've talked to Allan Jenkins, as far as I know he float coats his large cyanotypes.
    enjoy and be well

    Seamus
    www.seamusryan.com www.canvaszone.co.uk

  9. #19
    Davec101's Avatar
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    Quote Originally Posted by SeamusARyan View Post
    Hi Dave

    I assume you've talked to Allan Jenkins, as far as I know he float coats his large cyanotypes.
    Yeah i heard he does that, a bit too expensive float coating with Cyanotype II, it has been a while since i posted on this thread, at the moment i can coat 24x20 with a rod, it took a lot of practice and patience however at them moment I am getting good coats with a few failures here and there, thank goodness!
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  10. #20

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    Quote Originally Posted by Davec101 View Post
    Yeah i heard he does that, a bit too expensive float coating with Cyanotype II, it has been a while since i posted on this thread, at the moment i can coat 24x20 with a rod, it took a lot of practice and patience however at them moment I am getting good coats with a few failures here and there, thank goodness!
    What support surface below the paper are you using, plate glass?

    Tom

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