Sulfates in seawater

Discussion in 'Alternative Processes' started by NedL, Mar 4, 2018.

  1. NedL

    NedL Subscriber

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    This question is related to using sea water or sea salt for salted paper prints.

    This is probably wishful thinking, but if I took a cup of seawater and put it into a beaker full of calcite, and then filtered the result, would it remove the sulfates by precipitating insoluble calcium sulfate?
     
  2. Svenedin

    Svenedin Subscriber

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    I don't see (sea) this happening. sea water, sodium chloride and much else (including a little bit of sodium and potassium iodide). Your cacite is calcium carbonate presumably.
     
  3. Arklatexian

    Arklatexian Subscriber

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    You live much closer to seawater than many of the rest of us. Why don't you do this and find out. Seawater has taught us things in photography such as washing film and prints in seawater during World War II, before rinsing in fresh water, taught us to use hypo neutralizers.........Regards!
     
  4. Herzeleid

    Herzeleid Member

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    Ned,

    I don't know why you need to remove the sulfates but I made a few prints with sea water and lake salts.

    For a project of a friend I did a few prints using sea water, sea water from Crete to be exact. I have tested regional sea salt to make a print but I had great results with diluted sea water. Print made with the local salt had dark spots all over. I haven't attempted to remove any sulfates or other organics.

    I also made a few prints from local salt lake, Lake Tuz. The composition of Lake Tuz is mostly sodium, some potassium, calcium and very little lithium, but it contains good amount of sulfates too. I had the fastests exposures with this lake salt, the prints looked quite fine.

    I wonder why would you want to remove sulfates from the sea water.

    Regards
     
  5. RalphLambrecht

    RalphLambrecht Member

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    not fully sue what your goal is but, creating something similar to seawater isn't too difficult.
     
  6. jnanian

    jnanian Advertiser Advertiser

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    hello ned

    no clue about the sulfates but wynn white wrote about using tokyo bay water
    to make his salt prints
    http://www.alternativephotography.com/a-dash-of-salt/

    he gets great results ... california isn't too far from tokyo, maybe you will get similar results :wink:
     
  7. OP
    OP
    NedL

    NedL Subscriber

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    I should have been more clear why I'm asking! I've made prints using sea water and sea salt too. I haven't proved this yet, but I think the sea salt I'm using gets ever so slightly dark ( not obvious fogging, but subtle and difficult see if you aren't looking carefully ) right when the silver nitrate is brushed on. It's possible this is due to the sulfates or bromines in it, so I'm wondering if there might be an easy away to remove the sulfates.

    In fact, I've just finished reading Mark Kurlansky's book, Salt- a World History, and I've read a lot about salt production. I'm definitely interested in making my own salt for printing. It's pretty neat: the calcium chloride in sea water makes salt "sour" and the magnesium makes it "bitter" ( the word "bitter" comes from "bittern" which is the dregs from a salt evaporation pond! ). If you start boiling or evaporating sea water, the calcium chloride precipitates first, so it can be removed by letting it settle and then decanting. Then the sodium chloride starts to crystallize, and the fleur de sel forms a thin layer of crystals on the surface -- this is scraped off by hand and sold for a lot of money! If you keep going, finally combined magnesium-potassium salts start crystallizing and the trick for good tasting sea salt is to harvest it at the right time, before it is too bitter but when it has some sea salt "taste".

    By the way, Mark Kurlansky also wrote a book called Paper, Paging Through History, all about the history of paper making.. I just finished reading that one too! You can guess where this is heading :D
     
    Last edited: Mar 4, 2018
  8. Alan Johnson

    Alan Johnson Subscriber

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    [QUOTE="NedL, post: 2052212,] If you start boiling or evaporating sea water, the calcium chloride precipitates first, so it can be removed by letting it settle and then decanting. :D[/QUOTE]

    ? Calcium chloride is extremely soluble:
    https://en.wikipedia.org/wiki/Calcium_chloride
     
  9. Herzeleid

    Herzeleid Member

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    I will speculate, different silver salts precipitate in different colors, it is possible the different color you are seeing might be a result of that.
    Composition of sea water is complex with all the organic stuff in it, it might something entirely other than the sulfates or chlorides, as you mentioned may be small amount of bromine.
    I guess you will make a print and test it, if it clears well.

    Regards
     
  10. OP
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    NedL

    NedL Subscriber

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    ? Calcium chloride is extremely soluble:
    https://en.wikipedia.org/wiki/Calcium_chloride[/QUOTE]

    Thanks! I was summarizing some things I'd read a few weeks ago about homemade sea salt. It's just some "calcium salts" that precipitate first, which I mis-remembered/mistranslated as calcium chloride. That makes me wonder if the first precipitate might include calcium sulfate!
     
  11. Alan Johnson

    Alan Johnson Subscriber

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    If you want to remove sulfate from sea water, one way would be to add barium chloride which will precipitate out the very insoluble barium sulfate.
     
  12. OP
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    NedL

    NedL Subscriber

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    Thanks for all the replies. A series of tests has revealed that it was gelatin causing the effect I was interested in. I'll probably write a thread about it sooner or later. Interestingly, if you coat the paper I'm using (strathmore 500 drawing paper ) with this sea salt and let it dry, and then brush a couple stripes of silver nitrate on it and let it dry, the stripes are utterly undetectable. The same experiment with KCl or with kosher salt produced faintly visible stripes -- not enough that most people would worry about it, but detectable.
     
  13. Peter Schrager

    Peter Schrager Subscriber

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    Fukashima water right?...for making radioactive prints that glow in the dark
     
  14. OP
    OP
    NedL

    NedL Subscriber

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    You jest, but I'm planning to collect my sea water at Bodega Head or maybe one of the smaller beaches North of there. Recently cesium 137 has been detected there from Fukashima, about 3-1/2 times "normal" but still at an extremely low level. It was higher when atmospheric nuclear testing was still being done.

    If you scroll down this page, you can see a graph of cesium 137 from seawater collected about 20 miles from where I live. It's still way below what is even allowed in drinking water.

    The real time sensor is here, but it's not sensitive enough to pick up these very tiny amounts.

    So, in fact my salt prints will be slightly radioactive from Fukashima, but they won't glow in the dark! :smile:

    I have a nice salt print of Bodega Head but I don't think I have a scan of it anywhere.... here's a normal photograph:

    [​IMG]
    Bodega Head
    par Ned, on ipernity
     
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