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  1. #11
    keithwms's Avatar
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    First of all ask yourself what the maximum dark tone is possible with your setup/bulb etc... simply expose a piece of solution-covered paper without a negative or glass or plastic between. When you develop that test piece in water and peroxide you will see what the maximum tone is. Compare to the darkest tones you're getting through a neg. You may then discover that the darkest tone that you're getting (through the clearest portion of your neg) is still not getting where it could. If that is the case and longer exposure doesn't help, then you may have to consider the spectrum of your light source.

    Again, when you do this test, you should have *nothing* between the bulb and the coated paper... no plastic, no glass, no nothin'! The reason is that some glasses and some plastics will cut off the deeper part of the UV spectrum. Then you'd need to dose the clear portions much longer than you want in order to have good tones in the other portions. If that's the case then you will have to think about relative exposures and whether your neg has the right density etc. A step wedge is not a bad idea if you are wiling to take the time to figure out the best possible tone curve.

    Double coating does indeed give slightly darker tones, and then there is post-varnishing....
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  2. #12

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    Amuderick, what you do is practically converting the cyanotype image to one made with iron-gall ink, the resulting compound is the same/very similar... The problem is that iron-gall ink eats the paper in the long run, so beware if you value longevity...

  3. #13
    Vaughn's Avatar
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    To intensify the image, I have poured a dilute solution of Potassium dichromate over the print -- it really snaps it up. I pour it over the print while it is in an empty tray, then pour it back into the bottle.

    Works like magic, but I don't do many cyanotypes and dislike using dichromates except for when I have to.

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

  4. #14

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    Vaughn, isn't that practically the same thing as using a hydrogen peroxide bath? Both dichromate and peroxide are strong oxidizers... Nitric acid for instance, another oxidizer will do the job too if one wants to use even more exotic compounds.

    Regards,
    Loris.

  5. #15
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    Quote Originally Posted by athanasius80 View Post
    I finally got a source for Arches Platine and compared it to Arches hot press watercolor as my control. The Platine seems to consistantly make a lighter blue than the watercolor paper. I like Platine more and would like to switch to it, so does anyone know a way of making a deeper blue cyanotype? Examples are posted.
    Thanks!
    If your using the ware cyanotype sensitiser, to obtain darker results, after exposure place in a bath of citric acid, 30g per litre and agitate for a minute or so and then rinse with water as you normally would.
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  6. #16
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    They look a bit underexposed. Have you tried baking a plain piece of paper out in the sun, and then developing it to see the darkest blue that you can get?

    If you can get a nice, dark blue doing this, but when printing through a negative, can't get a deep blue without also bringing down the whites, the neg you are using is too low in contrast.

    I add a splash of hydrogen peroxide after development to speed the oxidization process that will eventually darken the print over time. This does not actually make it any darker than it would get eventually; just makes it happen immediately.

    IME, adding Kodak Indicator Stop Bath to the development bath lowers the contrast quite notably. It takes very small amounts to very finely lower contrast.
    2F/2F

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  7. #17
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    Quote Originally Posted by Loris Medici View Post
    Vaughn, isn't that practically the same thing as using a hydrogen peroxide bath? Both dichromate and peroxide are strong oxidizers... Nitric acid for instance, another oxidizer will do the job too if one wants to use even more exotic compounds.

    Regards,
    Loris.
    I am not sure. Does Mike Ware put a dichromate into his "new" formula as an oxidizer? or does it serve some other purpose? The effect of the dichromate is instanteous and extreme. I have never used the peroxide to see if the results were similar.

    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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    Hi Vaughn,

    In my knowing the minute amnt. of "optional" dicromate in Mike Ware's formula is for preservation (provides longer storage times before sensitizer gets bad), not extra density. Also as an additional benefit, dichromate additive slightly increases the emulsion's contrast for better compatibility with "normal" negative densities. (In this context normal defines a density range closer to traditional cyanotype requirements.) Without the dichromate you'll need a negative DR close to log 2.0 (almost) with New Cyanotype - which is considerably higher than what traditional cyanotype formula needs.

    You can try peroxide easily, just get the usual 3% drugstore version (which probably you already have at home) and add 5-10ml of this into 1000ml of "final" wash water. Agitate about 30-40 seconds (that's about where you don't see any change anymore), then do a final rinse in plain water and that's it.

    Regards,
    Loris.

  9. #19
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    Thanks Loris,

    The next time I make traditional cyanotypes, I'll cut one up into thirds after the water/development bath and do a little test with dichromate, peroxide, and no post treatment. Then let them dry and check them in a few days. Just out of curiosity. It might be a few months, so no one hold their breaths!LOL!

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

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