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  1. #181

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    Hereís a kicker.

    In my routine practice, I used spent developer as the washing aid after through fixing and quick rinsing. As long as your fixing is complete, thereís nothing more to develop, so you can reuse sulfite-containing mild alkaline solution (that is, used developer) as a washing aid. You probably donít need it to remove residual thiosulfate, but you do get significantly improved removal of sensitizing dyes, and save a lot of water and time.

  2. #182

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    I looked over my old lab notes. One thing I found to improve image quality is to use a mixture of triethanolamine, methyldiethanolamine, methylethanolamine, and dimethylethanolamine. The best proportion of the mix depended on the developer formula (mainly the pH factor). I would use these agents if liquid concentrate stock is to be prepared.

  3. #183

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    Quote Originally Posted by Ryuji View Post
    I looked over my old lab notes. One thing I found to improve image quality is to use a mixture of triethanolamine, methyldiethanolamine, methylethanolamine, and dimethylethanolamine. The best proportion of the mix depended on the developer formula (mainly the pH factor). I would use these agents if liquid concentrate stock is to be prepared.
    Wow! And these are only the chemicals that worked well for you, and not the many poor ones. You must have tried many different chemicals. Thanks for mentioning these. It's interesting that MEA and DEA are not in your list (but relatives are).

    Quote Originally Posted by Ryuji View Post
    In my routine practice, I used spent developer as the washing aid after through fixing and quick rinsing. As long as your fixing is complete, thereís nothing more to develop, so you can reuse sulfite-containing mild alkaline solution (that is, used developer) as a washing aid. You probably donít need it to remove residual thiosulfate, but you do get significantly improved removal of sensitizing dyes, and save a lot of water and time.
    If typical development is 7 min and fixing is 7 min, that's 14 min in an alkaline sulfite solution. Is that not enough to remove those dyes? Anyway, this is a clever idea.

    Quote Originally Posted by Ryuji View Post
    When Silvergrain products were offered commercially, I was strongly advocating among those who were involved to offer powder solutions.
    For one-shot use, would a user measure a certain amount of powder from the container to develop a roll? A different amount of powder is needed for a stainless steel tank versus Paterson-4, and for 35mm versus 120. And one roll versus two rolls. A different amount of powder could be measured for each case.
    My question is: How can we guarantee that the powder stays mixed well? I guess the user could shake the jar before measuring-out some powder, but I'm still not sure that coarse and fine powders would be mixed uniformly.

    Also, acid touching alkali (as powders) can cause problems, and I read in Mason about some ways of dealing with them. XTOL fixed the problem by having two packets. What method are you thinking of?

    A Merry Christmas to everyone!

    Mark Overton

  4. #184

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    Quote Originally Posted by albada View Post
    Wow! And these are only the chemicals that worked well for you, and not the many poor ones. You must have tried many different chemicals. Thanks for mentioning these. It's interesting that MEA and DEA are not in your list (but relatives are).
    Not the *only* chemicals. There is always good old sulfite.

    I tried a few pyrimidine (vitamin B) derivatives that worked well but too expensive for routine processing solutions. The ones that worked best were amino substituted at 2- and 4-positions. Those substituted only at the 2-position was ok as a developer additive but weak. Substitution at 4-position could be -OH. Incidentally, disubstituted pyrimidine was a decent developing agent. It would've made a decent press if I sold a developer using vitamins B and C as the developing agents, even at a price no one could afford, and hype it as "better than amidol and finer than glycin" and more exciting than Eikonogen or crap like that. People always like that kind of stuff.

    I just checked. 2,4,6-triaminopyrimidine is commercially available for about $60 for 25g. This is a decent developing agent. You can dissolve a few grams of this with carbonate and make a slow working developer. A vitamin B developer.

    I also tried imidazoles. They were more useful as a way to modify image tone and color than fine grain, though.

    I used diethanolamine and it is okay in small quantities (a couple of grams per liter of working solution) but I wouldnít use too much. Ethanolamine (monoethanolamine) - I didnít like much. Same kind of problems as ammonium salts though less severe.

    I did test a fair number of amines, because they could triple duty - as a pH buffer, chelator, and gentle silver complexing agent. I always had to blend two or more of them, because the one thatís best as the pH buffer for a target pH does not perform well for the other two functions. Some of these amines could have another duty of chelating calcium/magnesium from tap water. Ok, this is too much of my proprietary information.

    Just in case someone tries to get ahead of me and get patent on this... because these agents are not listed in the prior art, Iíll also say this... the substitution on the nitrogen may be not limited to methyl group but it can be larger group, ethyl, etc. It is just that methyl version is cheaper and easier to get (and less smelly).

    If typical development is 7 min and fixing is 7 min, that's 14 min in an alkaline sulfite solution. Is that not enough to remove those dyes? Anyway, this is a clever idea.
    You try once and youíll know. Soaking in spent developer for another 5 minutes and then soak again in tap water and take a coffee break. Youíll get nice clean neg. Bostonís tap water has pH of 9.2 but I think a bit of sulfite helps this process.


    See and discuss the rest of the stuff on the new thread I started.
    Last edited by Ryuji; 12-25-2011 at 03:25 PM. Click to view previous post history.

  5. #185

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    Propylene glycol (PG) reduces developer-activity.

    I was wondering why my concentrated developers were consistently less active than the identically-formulated ones directly mixed into water (without the PG carrier). Was I damaging the developers by heating the PG solution to 50C or with the extra handling? So I formulated one in water, developed a test-strip, then added 3.7% PG (by volume) and dev'd another strip. Significantly thinner, more than the extra 3.7% dilution could cause.

    Here's the 1-liter version of the developer I tested. Its image-quality is virtually identical to XTOL, with the same dev-times. I added ingredients in this order:

    Ascorbic acid ..................... 10.7 g
    Sodium metaborate ............. 7.5 g
    Sodium sulfite .................... 90 g
    Phenidone .......................... 0.15 g (use a 1% solution with PG)

    I'm hoping I can get the non-sulfite portion of this into a PG-concentrate suitable for 1+19 dilution.

    If you add boric acid and boost the alkali a little to get the same pH, the resulting developer is a little less active. Any idea why? Does the resulting buffer-system hinder activity somehow?

    Mark Overton

  6. #186
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    Did you check the pH of the comparable PG containing developer?

    Organics can sometimes change pH or distort their measurement.

    PE

  7. #187

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    Quote Originally Posted by albada View Post
    I was wondering why my concentrated developers were consistently less active than the identically-formulated ones directly mixed into water (without the PG carrier). Was I damaging the developers by heating the PG solution to 50C or with the extra handling? So I formulated one in water, developed a test-strip, then added 3.7% PG (by volume) and dev'd another strip. Significantly thinner, more than the extra 3.7% dilution could cause.
    Did you let the developer sit in a flask and see if there is any phase separation? (Like salad dressing made from oil and vinegar)

  8. #188

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    Quote Originally Posted by Photo Engineer View Post
    Did you check the pH of the comparable PG containing developer?
    Organics can sometimes change pH or distort their measurement.
    Yes, using paper test-strips, I've been verifying a perfect color-match with unused XTOL. I'm using XTOL as an 8.2 buffer.
    It's odd that 7% PG in a developer would have an obvious reduction in activity.
    My last test boosted the PG from 3% to 7% with a noticeable drop in density. I wish I had a better understanding of the chemistry behind all this.

    Quote Originally Posted by Ryuji View Post
    Did you let the developer sit in a flask and see if there is any phase separation? (Like salad dressing made from oil and vinegar)
    No, I tested the developer immediately after mixing, so neither concentrate nor working solution had a chance to settle. The working solution has now been sitting for hours, and a check a minute ago shows no separation.

    I can only conclude that PG hinders development for some reason.

    Mark Overton

  9. #189
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    Mark;

    PG is not known as a development inhibitor unless it is at very high concentration and then it acts like most organic solvents by inhibiting many of the very polar reactions of development.

    PE

  10. #190

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    Some exciting results!
    I finally have a developer that can be used as a concentrate with 1+19 dilution (i.e., it's a 20x concentrate).
    Compared to XTOL, it has: Lower contrast, same grain, very slightly better shadow-detail, same sharpness. In fact, I want lower contrast because I often shoot in contrasty situations, such as sun/shade, or harsh indoor lighting.

    I took PE's hint that the path to better image-quality means longer dev-times, so I reduced the alkali some, yielding this concentrate which produces 1 liter of working solution:


    Propylene glycol ................. 39 ml
    Ascorbic acid ..................... 10.7 g
    Sodium metaborate ............. 6.5 g
    Phenidone .......................... 0.15
    Propylene glycol to ............. 50 ml (you should only need to add about 1 ml)

    I poured all the chemicals into the PG at the same time, instead of waiting for them to dissolve separately. It took about 30 minutes of constant stirring at 50C to get everything to dissolve. Jerry suggests letting the brew sit overnight at room temperature, and that it'll all eventually dissolve without heating. I did this last week and it worked, but this time I was impatient.
    If I continue with this, I'll need to get a hot-plate/magnetic-stirrer combo.

    To use, you must separately add 90 g/L of sodium sulfite to the distilled/deionized water first so it'll scavenge oxygen, and then add the concentrate. If sulfite is measured volumetrically (and thus less accurately), then the same graduate can be used for both sulfite and concentrate, because the user will measure powder first, then liquid.
    Target pH is somewhere around 7.8-7.9 (I need a pH-meter!). Add 15% to XTOL's times, because this developer is similar to XTOL as it uses the same chemicals in similar proportions.
    It has no chelating agents, so I suspect it can only be reliably used with distilled/deionized water, and I still wouldn't trust a working solution that's over a few hours old.

    A question:
    Why is the contrast lower?
    I'll speculate that this developer has poor (nonexistent?) buffering because I removed the boric acid, and that causes the pH to drop more in dense areas, hindering development more in dense areas. That is, the poor buffering is causing compensation. Or am I off in the weeds about this?

    Other comments or criticisms about this developer?

    I know that to make this into a product, we'd want to incorporate a halide-solvent into the concentrate in order to eliminate the separate sulfite, and that lots of testing would be needed. I remember that Ryuji discovered a couple of films that worked poorly with his DS-10. That sort of knowledge only comes from thorough testing.

    I enjoy this...

    Mark Overton
    Last edited by albada; 12-26-2011 at 10:02 PM. Click to view previous post history.



 

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