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  1. #11

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    Thanks to all for responses.

    Lukas - I am not sure of the density range of the neg but it is substantially more contrasty than my normal offerings. I made the neg as a test on Cyanotypes (See the cyanotype here)

    Ole, nworth - I used table salt which has some anti-caking agents in it.
    Juan - I used a weak citric acid first wash. My water here is slightly alkaline and hard.


    Some things I can try differently next time:
    Use ammonium chloride,
    Use photographic gelatin,
    Add a citrate to boost colour and contrast.
    I will try and order a Stouffer step again (They ignore my emails) to monitor my density range.

    I can selenium tone a neg because I do have a copy. I would then be able to do a side by side comparison.

    At some point when I mix my own silver I will try the smieglitz suggestion.

    I am still unsure of the volume of sensitizer required (Silver Nitrate) to cover a 5x4. Is it more than the cyanotype sensitizer? Anyone have a rule of thumb that works for them?

    Cheers

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  2. #12
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    Quote Originally Posted by philldresser
    Thanks to all for responses.


    I am still unsure of the volume of sensitizer required (Silver Nitrate) to cover a 5x4. Is it more than the cyanotype sensitizer? Anyone have a rule of thumb that works for them?

    I've lately been using two coats of 1ml each for 8x10.
    juan

  3. #13
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    I have never heard of table salt containing any ferricyanide.

    Caking agents should not hurt you, but iodide, often found in table salt, will change the characteristics of the final material.

    PE

  4. #14
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    I think I had every problem possible until I switched to Kosher Salt. This coupled with negatives having a density range of about 2.1 produces very nice prints.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

  5. #15

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    Quote Originally Posted by Photo Engineer
    I have never heard of table salt containing any ferricyanide.
    It doesn't. But Morton kosher salt does contains sodium ferrocyanide (sometimes potassium ferrocyanide, yellow prussiate of potash) not sodium ferricyanide.

    To the poster who mentioned ferricyanide, be careful, ferricyanide and ferrocyanide are two diffent things.

    For photographic purposes it is better to use pickling salt.
    Last edited by Gerald Koch; 08-01-2006 at 09:47 AM. Click to view previous post history.

  6. #16
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    Quote Originally Posted by Gerald Koch
    It doesn't. But Morton kosher salt does contains sodium ferrocyanide (yellow prussiate of potash) not sodium ferricyanide.

    To the poster who mentioned ferricyanide, be careful, ferricyanide and ferrocyanide are two diffent things.

    For photographic purposes it is better to use pickling salt.
    Gerald, I wouldn't even want salt with ferrocyanide.

    Every mole will still liberate 6 moles of cyanide with enough acid such as the HCl in the stomach. At low levels this may not be toxic and may not even release the cyanide, but if it does it could cause breathlessness or dizziness in the person who consumes it.

    How odd. You learn something new every day. Now I have to check it out next time I'm at the supermarket.

    PE

  7. #17

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    It is not ecessary to switch to ammonium chloride, nor to use chemically pure salt - I did it first, and compared results with table salt which works fine, even with iodine, but this changes tonality, so I would use just the plainest, cheapest salt available in your local super market.
    The quality of the gelatine also should not matter too much (it's more important with gum prints and the like), though gelatine of dependable quality is available from Kremer pigments, and considerably cheaper than what you get in an alimentary store, at least here in Germany.
    First wash Water ph also does not matter at all with this process. The water just has to run milky.
    You will certainly improve results with citric acid added to the silver nitrate and/or to the salting (both is probably best), be aware that this reduces the permanence of the silver nitrate solution to a few months.
    About contrast: not being a subscriber, I cannot see your picture, but cyanotype is a funny process, more flexible than most people think. However, negatives for salt prints should be MUCH MORE CONTRASTY than what is normally thought adequate for c., more than for any other process exept pure palladium printouts. Density range should be about 3.0, that is, such a neg is useless for normal promide enlarging.
    I suggest you get yourself a 21 step Stouffer scale (google Stouffer) - very inexpensive, costs you less than a kg of ammonium chloride - and expose it alongside the negs you print. This gives you a very good idea of density ranges required for different processes and negs.

  8. #18
    Ole
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    Quote Originally Posted by philldresser
    I can selenium tone a neg because I do have a copy. I would then be able to do a side by side comparison.
    Instead of selenium toning, let me suggest bleaching and redeveloping in a staining developer.

    I've got good results from a "normal" negative that was bleached, then redeveloped in a "pyro/soda developer": 1/2 liter of water, 1 tsp pyro, 1 tsp soda (NaOH). No sulfite at all, so the developer dies within minutes. Mix each constituent in half the final volume, then mix the two immediately before putting the negative in.
    -- Ole Tjugen, Luddite Elitist
    Norway

  9. #19

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    The amount of ferrocyanide in Morton kosher salt is quite low and not dangerous. BTW, a dilute solution of hydrocyanic acid was once used as a treatment for excess stomach acid and heartburn. No it wasn't a permanent cure. ;-) As far a poisons go there are many things far more poisonous than cyanide.

    As I said, pickling salt is probably the best choice when sodium chloride is needed for photographic purposes. There are no insoluble anticaking chemicals in it like silica. Works very well for homebrew Microdol-X or Perceptol and should be fine for alternative processes.
    Last edited by Gerald Koch; 08-01-2006 at 01:25 PM. Click to view previous post history.

  10. #20

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    Lucas

    Attached is the cyanotype for reference. Density is definitely not 3.0.

    Ole. Do you think it would be worth trying to redve in Pyrocat-HD. Is this staining enough?

    Phill
    Attached Thumbnails Attached Thumbnails fruit.jpg  
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

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