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  1. #1

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    Micro Purple Spots on B&W Negatives?

    Alright . . .

    I need some help in identifying a problem.

    I have noticed this problem quite consistently on my 35mm and 6x6 negatives (arista.edu) developed in various sized Patterson tanks/reels with Arista developer and Arista fixer. This problem ultimately shows up on the print.

    When I have a 35mm or 6x6 negative in my enlarger (blown up to 5x7 or 8x10) and when I am in the process of focusing the image using my eye focuser, I sometimes notice small purple gunk/spots/rings on my clearly grey tone negatives. The rim of the ring is purple, and the interior is usually transparent or transparent with a purple spot in the center (making a ring or donut). These spots are difficult to see with the naked eye on the negative or contact print, but blown up and made into a print, they create some awfully noticeable dark spots and/or rings (if they appear on human skin, they look like a dark, nasty pimple).

    My first guess is that there are small air bubbles during developing that form these spots, but think I am doing every thing correctly and since these spots are purple (rather than the same color as the neg emulsion) maybe it has something to do with fixing/washing?

    Here is my process: Pre-wash 5 minutes w/tap water, developer (firm taps to dislodge bubbles), stop, 4 min. fix, wash with running tap water 15 mins, add photo flo.

    Anyhow, need help in identifying/fixing the problem. Any thoughts or experience with annoying purple gunky spots on negatives would be greatly appreciated! Thanks.

    Dave

  2. #2
    billschwab's Avatar
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    Dave. The fact they are purple makes me think your problem may be bubbles in the fixing process and the film in these spots is not clearing completely. It seems unlikely as the film would be thoroughly wet at the time of fixing, but there is still a chance this could be the problem. Do you agitate the film right through the fixing process?

    What about the drying area. Is there a chance something could be splashing onto the film while it is drying?

    Bill

    www.billschwab.com

  3. #3

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    Thanks Bill for the reply. For the first 30 secs of fixing, I agitate. Then 5 secs of agitiation every 30 secs (2 twisty, inversions)

    I store the negs in a save, dust free locker, so I don't think anything could be splashing on them during the drying process.

    I will munch on the fix idea. Thanks again.

  4. #4
    noseoil's Avatar
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    Sounds like fixer to me. tim

  5. #5

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    Just some thoughts... I know you said you rap the tank after the developer ...I give the tank some raps after developer, stop and fix are poured in.

    I read somewhere that too strong a stop dilution can cause air bells... (I use plain water instead of stop). Some say it is not true, but it has eliminated my air bubble problems.

    You could also have contaminated fix if you re-use it too many times.

    Best to try with fresh chemicals..

    I hope this helps,
    John

  6. #6
    Donald Qualls's Avatar
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    Those rings could also come from bubbles at the wash stage -- if your last wash is still carrying off dye from the negatives (as my PhotoFlo bath sometimes has done), a bubble or drop left on the film could redeposit the dye as it dries. I've found, when I have streaks or blotches of dye on my sheet film (because the base side is in contact with the tube surface), that I can quickly clear/decolor the dye by soaking the (fixed, unwashed) film for a couple minutes in a 2% sodium sulfite solution to which I've added a small and noncritical amount of sodium carbonate -- I use 1 tsp for 22 ounces, because that's how much it takes to cover my film sheets in the graduate I use for this step, but I wouldn't expect half or twice that much to make a real difference.

    My theory is that the alkali "reopens" the gelatin after the acid fixer has "closed" it, allowing the dye to escape readily, while the sodium sulfite decolors the dye some way (since the solution doesn't pick up color the way my developer does and wash sometimes has before I started this). Leaving the gelatin in an alkaline condition has the added advantage or speeding washing or making a given wash regimen more effective at removing residual fixer and complexed silver; I'm considering adding this step to my roll film process as well.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  7. #7

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    Quote Originally Posted by Donald Qualls
    I've found, when I have streaks or blotches of dye on my sheet film (because the base side is in contact with the tube surface), that I can quickly clear/decolor the dye by soaking the (fixed, unwashed) film for a couple minutes in a 2% sodium sulfite solution to which I've added a small and noncritical amount of sodium carbonate -- I use 1 tsp for 22 ounces, because that's how much it takes to cover my film sheets in the graduate I use for this step, but I wouldn't expect half or twice that much to make a real difference.
    Donald,

    How do you mix 2% sodium sulfite solution (with sodium carbonate)? Can you do this with houshold ingredients? My 4x5 taco's have been leaving the dye even after 20min wash's having moved the rubber bands. Last night I accidently left 2 sheets in a tray of distilled overnight and the dye is still there!

  8. #8
    Donald Qualls's Avatar
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    You probably can't get sodium sulfite as a household ingredient -- I have a couple liters of a stock solution I made up several months ago, and have stored in a tight plastic jug with minimum air (so, hopefully, it's still close to the original 20% strength, not too much converted to the sulfate yet), but it was Kodak brand and I bought it in a large photographic shop. You can get the same stuff in generic brand from Photographer's Formulary or wherever Aussies buy their raw chemicals -- sodium sulfite isn't particularly esoteric; you might even find it at butcher shops or brewers' suppliers and the like, since it's also used as a food preservative. The one pound jar I bought cost, IIRC, about US$5 with the Kodak label on it.

    Sodium carbonate, in my case, is Arm & Hammer brand "washing soda" or what some parts of Europe call "household soda" -- it's sold as a detergent enhancer and fabric deodorizer, at least in this country. Costs about US$3 for a big box, probably a decade supply at the rate I use it.

    So, starting with the 20% sodium sulfite solution, I put two ounces in a graduate, add water to make 22 ounces, and then stir in a teaspoon of the washing soda power. When the cloudiness is cleared up, it's ready to use.

    You could probably do the exact same thing with Hypo Clearing Agent, if you have that -- it's mostly sodium sulfite anyway, though I don't know the strength so can't recommend a dilution factor. Dilute so its 2% strength sulfite, and then add the washing soda as before.

    Lacking the sulfite, you'll get some improvement in the dye with plain alkalized water, using either washing soda or borax; here, you're just washing the dye out of the gelatin rather than decoloring it, but it takes a lot longer and still requires longer than normal washing after alkalizing the film.

    Best of all, get an alkaline fixer and take off the rubber bands after half the fixing time -- you'll never see the dye again. There's plenty of sulfite in commercial fixers to do this, as long as the solution is alkaline to keep the gelatin "open".
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  9. #9

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    thanks... I do have Hypo Clear so I'll try that 1st, then source some sodium sulfite (photo store that does have these things is acros the other side of town)

  10. #10

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    Has anyone come up with other ideas regarding this bubble pinhole problem?

    I am experiencing the same issue. I get tiny bubbles throughout the frame. These are almost invisible to the naked eye. They show up as dark dots in the image when looking at the negative. Take a loop to the film and they appear as tiny bubbles. Print the image and you get pinholes.

    This problem is *film* specific. I have developed Agfa APX 100 and Fomapan 400 in the same chemicals, during the same developing session, and had no issues. The Agfa and Foma films were developed last, after 6-8 Arista.Edu (Fortepan) 100 rolls went through the same soup. If the fixer was exhaused, or I was not agitating enough, the problem should have shown up with these other emulsions, but did not. In fact, one of the rolls of APX was left in the fixer completely un-agitated. No issues.

    I have developed these films with HC-110 1-62 and with Diafine. Water was used for stop bath and Ilford fixer. I pre-soaked at first, then stopped.

    Donald has mentioned temperature in the past. My temperatures are higher than 68F/20C. Depending on the season, much higher. I will try to cool the chemicals down and see what happens.

    Any other ideas? I would love to hear from others who use (the now replaced) Arista.Edu 100 roll film.

    Thanks.

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