Processing tip: mixing fixer

Discussion in 'B&W: Film, Paper, Chemistry' started by michael_r, Oct 15, 2011.

  1. michael_r

    michael_r Subscriber

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    Most experienced darkroom practitioners agree one of the keys to making high quality negatives is consistency. One of the more common issues less experienced photographers seem to encounter, and write about on here, is improper fixing. While there are various causes, for those less experienced, here's a tip which might potentially help before the fixing process even begins.

    We all diligently mix chemicals when they are in powder form, because there is visual evidence of insufficient mixing. However proper mixing can easily be overlooked when mixing liquid concentrates with water. A good example is Ilford Rapid Fixer. It's not written on the bottle, but if you read Ilford's tech publication for this product, you'll find an important note regarding the suggested mixing procedure. The concentrate doesn't mix readily with water. Therefore Ilford recommends first pouring the required amount of concentrate into the mixing vessel, and then slowly adding the water while stirring. Don't just pour the concentrate into water (or vice versa) followed by a quick stir. Just because two substances are both in liquid form doesn't mean they don't require thorough mixing.

    Actually this highlights another point - consult the product support materials provided by manufacturers like Kodak, Ilford etc. There is often a lot of good additional information not always included in the short form instructions.

    Michael
     
    Last edited by a moderator: Oct 15, 2011
  2. BugraK

    BugraK Member

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    Interesting. Thanks for the tip.
     
  3. Worker 11811

    Worker 11811 Member

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    I always mix until the schlieren effect disappears.
    Sometimes it takes a minute to completely disappear.
     
  4. octofish

    octofish Member

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    Whenever I'm diluting anything (including fixer), I pour the concentrate into the mixing container first. I then add a small amount of water to the measuring container I just used, swish it around, and pour it into the mixing container, repeating a few times and mixing as I go. I do this primarily because it ensures I get all of the volume of concentrate I just measured into the mixing container. But based on the above, looks like this is probably a good thing for even mixing also. Happy days!
     
  5. deleonjayson

    deleonjayson Member

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    A valuable piece of information. Thanks.