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Thread: The Uranotype Thread

  1. #1
    tgtaylor's Avatar
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    The Uranotype Thread

    Yep, uranium prints.

    Untitled - San Francisco, 2016.



    Printed on Hahn Platinum Rag from a 5x7 Ilford FP4+ negative. This is the first Uranotype that I have made and I may have printed it a little too deep.

    Thomas

  2. #2
    Mark Sawyer's Avatar
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    Re: The Uranotype Thread

    Looks like potassium ferricyanide developer? I always liked the silver nitrate developer. Soooo many options with uranium prints! A nice image for the very warm tone!
    "I love my Verito lens, but I always have to sharpen everything in Photoshop..."

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    Re: The Uranotype Thread

    Let me beat someone to asking: AFAIK ALL Uranium isotopes are radioactive---though not all are particularly dangerous. What kinds of handling precautions do you use? Who sells the chemicals? I've never looked to buy any so maybe the usual places sell it, I wouldn't know. Besides the undeniable weird/cool/market differentiation factor, what exactly is the reason for using radioactive photo print chemistry?

  4. #4
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    Re: The Uranotype Thread

    Thanks Mark. Yes, it's the potassium ferri (10%) developer - I didn't know there are other developers for the process. Googling "Uranotype" is returning far more links now than just a few days ago. Whether or not this is due to my searching alone or an increased interest in the process I don't know but I sure am glad for the increase. The main problem from what I can see is an appropriate subject for the process. From my research it appears that portraits were the favored subjects in the 19th and early 20th century.

    Thomas

  5. #5
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    Re: The Uranotype Thread

    Fr Mark: It's depleted uranium so while it is mildly radioactive - a very sensitive meter will register about 2x above the normal background radiation when placed very close to the paper but undectible from the background a few inches further away. The main problem is the toxcitity. I wear a mask, gloves and googles when measuring, mixing, and coating. As with all other processes I don't use a blow dryer to speed things up but let air-dry face up. You don't want any liquid on your body or uranium atoms in your lungs.

    Thomas

  6. #6
    Mark Sawyer's Avatar
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    Re: The Uranotype Thread

    Sorry, just having the devil of a time getting the attachments right! Here are a few old formulae for developers that give different colors in uranium printing, from Modern Heliographic Processes (Ernst Lietze, 1888):
    Attached Thumbnails Attached Thumbnails Uranium 1.jpg   Uranium 3.jpg  
    "I love my Verito lens, but I always have to sharpen everything in Photoshop..."

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    Re: The Uranotype Thread

    Beautiful print and a very interesting tone. I've always found this process fascinating, but haven't actively looked for the chemistry. The toxicity worries me a bit, too.

  8. #8
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    Re: The Uranotype Thread

    Thanks Mark. I used a 25% or 4 to 16 ratio (8gm to 32mL) for the sensitizer as suggested by Bob Schramm http://unblinkingeye.com/Articles/Uranium/uranium.html but thought that 4 grams was excessive. I use a 11% solution of silver nitrate for salt prints and they come out great. I have about a gram left so I'll mix up enough to make a print or two of the black type. For the right subject matter, the red-brown is killer.

    For anyone interested, here is a recent you tube video on the process: https://www.youtube.com/watch?v=iwXuZwtjHks He goes way overboard IMO with the mask used and elbow length gloves: uranyl nitrate is not like talcum powder but a mostly granular compound
    so you don't see anything floating up in the air when pouring it to be measured. I use a 100mL pyrex measuring beaker on an Ohaus digital scale and then pour in the measured distilled water and stir with a pyrex rod. It quickly dissolves into solution. I don't question the toxicity but its an easy one to work with. I use gloves, a Particulate Respirator / Surgical Mask, and chem lab goggles that I used in college chemistry.

    Thomas

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    Re: The Uranotype Thread

    As a former chemist, I'm always tempted to try new and interesting chemistry, jus, but I may just content myself with enjoying the prints you post when it comes to this technique.

  10. #10
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    Re: The Uranotype Thread

    Untitled - San Francisco 2016



    This is the 3d printing and the best. The 2d consisted of an addition to the senstizer and an an adjustment to the exposure time. This one, the 3d, consists of a further refinement to the composition of the senstizer and another adjustment of the exposure time. Love the brown russet/bartolozzi red coloration.

    Thomas

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