2-part glycol developers

Discussion in 'B&W: Film, Paper, Chemistry' started by Photo Engineer, Oct 22, 2005.

  1. Photo Engineer

    Photo Engineer Subscriber

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    Jay, stain and contrast usually go down with pH and stain (fog) and contrast tend to go up with pH. TSP will raise pH quite a bit while TEA and borate tend to keep it down. Mixtures move around quite a bit depending on ratio as none of these combinations represent good buffers.

    How is the weather out there for riding? Must be good or you wouldn't be going. Here it is cold and rainy. Typical Saturday in Rochester. The weather seems to know when a weekend rolls around and is statistically worse then. Well, maybe that is why George Eastman went into photography. The weather was conducive to doing lots of indoor darkroom work.

    PE
     
  2. ongarine

    ongarine Member

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    What is TSP?
     
  3. Photo Engineer

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    Jay, treat TSP as if it were Sodium Hydroxide. It will absorb CO2 out of the air and go bad slowly so keep it in full tightly capped bottles. It can etch glass a little in high concentrations, and can certainly etch skin. Take care with it. I use it to wash walls before painting. It is a good cleaner.

    It is a good alkali to use in developers and is generally underused as it is a poor buffer at the pH it likes to start at. For single use or two part developers it would be ideal though.

    It is used in E6 IIRC.

    I'm looking forward to seeing some of those results in person. I'm working on some HA developers myself.

    Good luck.

    PE
     
  4. Photo Engineer

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    High Acutance.

    PE
     
  5. Jordan

    Jordan Member

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    Hmm. I always thought TSP would cause problems with precipitation of insoluble phosphate salts from mineral-rich water. (I guess carbonate causes the same problem, yet we use it anyway.)

    Interesting idea. TSP is available at just about any hardware store, at least around these parts (Toronto).
     
  6. Photo Engineer

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    Jay, no.

    Jordan, if you have any precipitate, just add some Quadrofos or Disodium EDTA to the developer (about 2g/l). That should fix you up.

    However, usually water is not that hard that a lot of ppt forms from phosphates. And, Calgon was a phosphate containing material at one time (but not TSP of course). Sometimes phosphates form soluable complexes.

    PE