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  1. #1
    msdemanche's Avatar
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    Does anyone know how I reversed HP5 from a negative to a positive?

    Well,
    I am interested in anyone that understands just what I accidentally did to one negative. I am shooting with my Holga with about a 10 count exposure. I then process the negs in HC110 1-31 dilution. That leaves very black (bullet proof negs). I then put them in a Farmer's reducer from the darkroom cookbook, tray bleaching back and boom, the image appears. Now the bleach is not really agitated this gives the unique ebbs and flows you see in these images. Ok, now sometimes the image becomes very thin and on one image (Santa on a Harley) it seemed too thin for my taste. I decided to intensify the negative and put it in a intensifier. Well, I must not have looked at it closely when I scanned the neg, because the film scanner was set to positive, hence the image I posted in my photos. Today I went to print and was surprised to see a beautiful 9"X9" negative on my paper.
    I know enough about transparency film to know there is silver there, but did I do something that is normal, or have I made a freakish HP5 positive. I know there are folks out there that understand the process and how I managed this one.
    I will wait for my scolding and answers.

    Michel

  2. #2
    Christopher Walrath's Avatar
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    Wirelessly posted (BlackBerry9000/4.6.0.167 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102 UP.Link/6.3.0.0.0)

    Solarization can cause a reversal of density values in a neg under extreme circumstances. However I doubt ten seconds wasd enough to do that.
    Last edited by Christopher Walrath; 05-06-2009 at 04:17 PM. Click to view previous post history.
    Thank you.
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  3. #3

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    What intensifier are you using? I don't see the image you posted.

  4. #4
    msdemanche's Avatar
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    Peter,
    I have attached the positve scan of the image in question. I know was a postive when I made the print yesterday it was a negative. I checked my film scanner and it was set to postive, so, well..... Now to the intensifier, I used Monckhoven's formula #179 in the old edition of the Darkroom Cookbook. I intensified only this one negative, so I did not expect the reversal.
    Hope that can help answer the question.

    Michel
    Attached Thumbnails Attached Thumbnails santa_on_a_harley.jpg  

  5. #5
    msdemanche's Avatar
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    I just scanned the print I made from the image in question you can see that it is a negative image, I am interested in folks thoughts. It should not have solarized.

    Michel
    Attached Thumbnails Attached Thumbnails santa_small.jpg  

  6. #6

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    I don't have the book handy. Searching online for Monckhoven's intensifier yields a formula that contains mercury and cyanide, which I trust you didn't use. Can you post the formula?

  7. #7
    msdemanche's Avatar
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    First please everyone know that I am working at my University's darkroom. Great ventilation, superb chemical storage and very good environmental standards. I also have ther correct gloves, and respirator to play with this kind of stuff.
    That said the formula:
    15.0 grams sodium cyanide 500 ml water. dissolve that and then mix with 22.5 grams of silver nitrate crystals and 500ml of water. This creates a milky solution. That must sit and then I used a filter to make the final bath. I then put my film in it.
    So far all to whom I have spoken do not know how I did it. So i am going to try and replicate the process and see if it happens again.

    Michel

  8. #8

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    The sources I see cite Monckhoven's formula as starting with mercuric chloride bleach. Did you omit that step? In either case, I'm not sure anyone here has much of a clue as to why you got a reversal - you're possibly the first person in decades to try Monckhoven! Would be pretty cool if it was a repeatable way to get reversal of tones, but the cyanide would be a big stumbling block.

    Agfa 600 is a safer single-bath alternative:

    Add to 500 ml water:
    citric acid 1.5g
    hydroquinone 1.5g
    silver nitrate 2.5g

    10 min is about a 2-grade increase
    Last edited by psvensson; 05-07-2009 at 02:16 PM. Click to view previous post history.

  9. #9

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    Did you stop and fix your negatives after the first development step? Or did you skip this step completely?
    "Lo único de lo que el mundo no se cansará nunca es de exageración." Salvador Dalí

  10. #10

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    Farmer's reducer contains fix, AFAIK.

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