silver migration

Discussion in 'B&W: Film, Paper, Chemistry' started by LisaU, Feb 22, 2008.

  1. LisaU

    LisaU Member

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    I posted a problem I had a while back about teardrop shaped spots on the emulsion side of my negatives after drying. I have done many tests and low and behold I finally found that if there are any small drops left on the other side of the neg, a spot appeared ( teardrop shaped ) on the emulsion side. I found that because that spot took much longer to dry, the silver ended up migrating to the edges causing the destructive shape.

    I have been using Ilford Hypam Fixer without hardener, would using fix with a hardener help keep this from happening?

    I use Neopan 400 film and I do use distilled water with photoflo in it already. I don't squeegee my negs but I now have to go back after about 5 minutes of hanging and carefully wick away the few small drops that may occur with the tip of a chamois cloth. I must be doing something wrong because it just doesn't seem like everyone is having this problem. But since I have been doing this, no spots. Maybe Neopan 400 is just a bit too soft and needs that hardener in the fix?

    -lisa
     
  2. Neal

    Neal Subscriber

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    Dear Lisa,

    Good news, the silver isn't migrating and you don't need a hardening fixer. If you are getting beads of water on your film you are not using the photo-flo and distilled water correctly. The water should run off evenly. When you mix your photo-flo with distilled water, make sure you are pretty close to the concentration advised on the bottle. Let the film sit in the photo flow for a couple of minutes (agitate for the first 30 seconds). Two "tricks" that I've read are handy. If you can, hang the film on a bit of an angle so that the water/photo-flo mixture runs to one side of the film. Rinse down the film with the photo-flow mixture once it is hung, this gets rid of any bubbles from the photo-flo.

    Hardening fixers
     
  3. Dietmar Wolf

    Dietmar Wolf Member

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    Hi Lisa.

    When you take the film out of the tank it is still in his spool. Wave that spool in the air. Fast forward and backward, several times.

    You will remove all the water. No water -> no problem with water. You could even stop using photoflo, using only distilled water :wink:

    After that, take the film out of the spool and simply dry (without wiping, thats really not good, I personally think).


    Best regards, Dietmar
     
  4. LisaU

    LisaU Member

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    Thank you Neal and Dietmar for your replies. I haven't been using the photo flo at the concentration it says on the bottle. For a 4 reel tank I've only been using about 5 or 6 drops with distilled water. Maybe that is my problem. I also use the method Dietmar suggests to the T. I take it out of the last dunk on the reel and wave it to get as much water out as possible before hanging. I actually don't get "water spots" per say, just that weird "silver migration thing" or so I thought. Oh, and I never wipe my negs. I just touch the drop with the cloth so that the cloth sucks in the excess water. The cloth doesn't actually even touch the negs. I don't think wiping is good either.
    thanks,
    lisa
     
  5. JohnFinch

    JohnFinch Member

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    Hi Lisa,

    It does sound like you have some kind of contamination in your water. This could be coming from residues left in the film from development. How are you washing the film? Here's the best way I have found.

    After fixing fully rinse the tank and film, then fill the tank with distilled water, pop the lid back on and invert 5 times. Leave standing in this water for 5 minutes.

    Then empty the water and fill again with fresh distilled water. Invert 10 times and leave for 5 minutes. Empty out.

    The fill with fresh distilled a third time, invert 20 times, leave standing for 5 minutes.

    After this you empty the water out and use your photoflow with distilled water. As the previous poster rightly said, agitate for 30 seconds and leave to soak for just a couple of minutes.

    Your film is now archivally clean and you can hang it in the shower to dry. Yes, hang it in the shower after you ran the shower hot for a few minutes and filled the shower room with some good old steam (you don't need to see steam, just know it's very moist in there). This steam drags any airborne dust down to the ground so it doesn't attach itself to your wet film.

    John
    pictorialplanet.com
     
  6. LisaU

    LisaU Member

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    Hi John,
    I wash my film in a film washer for 20 minutes then I drip drain any tap water out then I place it into a tank with distilled water and photo flo. My concern is also when I did have to rewash an already cut neg, from a previous week ( there was a small piece of dust stuck to it), the dust came off easily and I then redunked in distilled and photoflo. But when it was hung to dry a small drop of water clung to the nonemulsion side. On exactly the opposite side of the small water drop, the emulsion stayed swollen in just that area and the migration happened where it wasn't there earlier. I don't get a water drop stain on the nonemulsion side, just the density shift in the emulsion.
    I usually only let the negs stand in the distilled water/photo flo mixture for 1 minute and agitate only once. I do think I do wash well with film washer. I also hang my negs in my neg dryer but I don't turn on the heat. It is just a closed space. There is no air circulation though so maybe this contributes to the slowness of the drying?
     
  7. JohnFinch

    JohnFinch Member

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    Lisa,

    Interesting. Is your water hard? If there is calcium in the tap water it will contaminate right in the emulsion and leave the kind of marks you describe. Soaking the film in the photoflow solution will not remove this contamination. Try just one film the way I described and see that you don't have the problem anymore.

    My father, who is still an avid photographer after 70 years(!) lives in an area of hard water. When he's just doing film/developer tests he doesn't go through the archival washing procedure but just rinses it with running water for 30 minutes before a quick photoflow. Then, he dips his fingers in the photoflow and wipes two fingers down the film like a squeegy (one on each side) . This removes the laying water and, when dry, he gets no water marks. I don't think this is good practice when it's a keeper but it certainly stops his water mark problem.

    John
    pictorialplanet.com
     
  8. JohnFinch

    JohnFinch Member

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    Oh, BTW, the small droplets of water on the non-emulsion side are keeping that area of the negative cooler (called the latent heat of evaporation... it cools things). That's why opposite these drops the emulsion is drying more slowly allowing the contaminants to move to the edge of the drying area. It's like a coffee filter paper. When it dries there's a dark line at the very edge where more 'contaminants' have been drawn.

    John
    pictorialplanet.com
     
  9. LisaU

    LisaU Member

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    Hi John,
    I will definitely try your method this weekend. I think you hit the nail on the head. I live in Hawaii and I'm pretty sure my water is soft but now I'm not sure because I think you are right. Do you know what test I can get to see what kind of contaminates are in that particular tap. So soaking it in a total of four baths of distilled water will clean the contaminates out of the emulsion? That's a lot of distilled water. If I do it like your father ( kind of the way I have been doing it - making sure there are no droplets on the non emulsion side) will my negs hold those contaminates and pose problem later?
    Thank you.
    -lisa
     
  10. lee

    lee Member

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    lisa,

    how are you mixing your photo-flo? I see a lot of photogs mixing the photo-flo to strong and that will cause scum on the film. I generally make a touch weak and then I shake the can and move the reel up and down pretty vigorously. I remove the reel from the tank at about 30 seconds and while firmly grasping the reel I shake the reel and watch the suds and water fly off the reel and film. After that, I remove the film and hang to dry. I never squeegee or touch the film again until it is dry. Using this method for over 30 years now and spot free films.

    lee\c
     
  11. blaze-on

    blaze-on Member

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    Excellent work Lisa...website is efficient too..
     
  12. LisaU

    LisaU Member

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    Lee, that is actually exactly how I do it. I mix my distilled with about 5 drops of photo flo in a 4 reel tank. I follow with how you do it with the shaking and hanging word for word. I have looked at my film as soon as I hang for those spots and they are not there, only after drying. If anything, I think I don't use enough photo flo. How much do you use?

    Matthew - thanks for the shout out. :wink: My site is like 6 years old ( I keep nagging my husband to update) so I now post my new work on my blog.
     
  13. MattKing

    MattKing Subscriber

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    Lisa:

    5 drops sounds like a lot of photo flo to me. I would try using less - probably starting at 1 drop.

    Matt
     
  14. lee

    lee Member

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    Edwal makes a low foaming photo-flo substitute that might be worth trying to find. LFN is the name. you might try that.

    lee\c
     
  15. JohnFinch

    JohnFinch Member

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    The way I describe for washing your film (5 inversions wait 5 mins etc etc) has been offered by Ilford for donkeys years as archival. This means that it washes all the contaminants out of the film emulsion.

    If you think that you will use your negatives in 5, 10 or 20+ years from now (and I bet you probably will) then you must wash out all the contaminants. Otherwise your film will decay.

    Here's a link to the method I know works very well...

    http://web.mac.com/johnfinch/PictorialPlanet/Beginners_Film_Developing/Entries/2008/2/22_Washing_Film_and_Paper.html

    If you do what my father does with his test films then your negatives won't last and you'll keep getting these spots on the emulsion.
     
  16. LisaU

    LisaU Member

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    I have washed with with the Ilford method before. I actually do it when my water temp from my tap is too warm. If it comes out at the right temp ( which is usually ) I use my film washer. Either way I do it, I use water from my tap and not distilled until the last dunk with photoflo. I'll try and test my tap water first for contaminates and in the meantime, I'll use distilled for all washes. Thanks John.