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  1. #1

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    Amidol/Propylene Glycol stock solution tests

    On June 22, I tried dissolving 8 grams of Amidol in 150ml of Propylene Glycol (PG). I put 150ml of PG in a 300ml Pyrex beaker dropped in a stirring magnet (Teflon coated) and poured in 8 grams of Amidol. Some of the Amidol slowly went into solution at room temperature (dark blue solution color). I increased the temperature with continuous magnetic stirring (under a vented chemical hood). Most of the Amidol dissolved by the time the solution reached 170 deg. F. I continued heating and stirring until the solution reached 270 deg. F. I could see that there was still some undissolved residue at that temperature. I slowly cooled the solution and decanted it into a bottle. There was about a gram (estimated) of undissolved material left in the beaker. I added 30ml of methanol to this residue, stirred and it dissolved (violet color). I added this to the PG mix (now a indigo color) and saw no color change. I have been watching this solution for changes (color, activity, etc).

    It has now been 22 days since I mixed the solution of Amidol (8 grams) in a mixture of 150ml propylene glycol and 30ml methanol.

    The color of the concentrated Amidol/PG mixture remains an indigo blue (unchanged from the time I mixed it).

    Today (7/13) I mixed a small amount (about 80ml) of a dilute Amidol working developer solution. I used about 2 - 3ml of the concentrated Amidol stock solution. The rest of the working solution followed Michael Smith's Azo formulation.

    I used the leader off an old (1989 Expry) roll of 35mm Tech Pan. I cut the leader into 2 pieces, fixed one piece and dropped the other piece into the beaker containing the dilute Amidol solution. The film piece turned black in about a minute. I left it in the Amidol for another minute, then washed it, fixed it in TF-4 (probably a mistake), washed and dried it with its fixed-only companion piece.

    The developed piece is obviously stained, the stain color is green/black. The stain is not uniform and I suspect the TF-4 fixer may have removed some.

    Color transmission densitometry of the developed piece shows:
    Visual Channel Density = 1.17
    Blue Channel Density = 1.46

    The fixed-only piece shows:
    Visual Channel Density = 0.13
    Blue Channel Density = 0.10

    I covered the beaker and will check the developer activity again after 8-10 more hours.
    Tom Hoskinson
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  2. #2

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    Thanks for that Tom. Can you explain what your procedures are going to achieve and what you are hoping to find or not as a result? Are you simply testing for whether or not the developer is still as active as when first mixed? Will you be trying this out on some "scenic" negatives as well? Many thanks for sharing your research with all of us.
    Francesco

  3. #3

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    Quote Originally Posted by Francesco
    Thanks for that Tom. Can you explain what your procedures are going to achieve and what you are hoping to find or not as a result? Are you simply testing for whether or not the developer is still as active as when first mixed? Will you be trying this out on some "scenic" negatives as well? Many thanks for sharing your research with all of us.
    Yes Francesco,
    I am preparing to do Azo/Amidol printing of some of my 8x10 negs next Saturday and I wanted to run a developer activity "proof test" on my Amidol/PG stock solution before then. There are a lot of stories about how Amidol solutions can "go bad" without changing color.

    I also have 8 new sheets of Efke 100 to process (probably Thurs. night). All are landscapes/nature subjects and some were multi-second exposures made with my Polarfleece Sock/Shutter.
    Tom Hoskinson
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  4. #4

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    Tom,
    Thanks for the update. The question that I have is why use film to check amidol activity?, or is this simply because the film is much more susceptible to determination of Amidol activity?, or... are you wanting to arrive at a new film developer based on Amidol? Thanks again for your continued service...

  5. #5

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    Quote Originally Posted by Donald Miller
    Tom,
    Thanks for the update. The question that I have is why use film to check amidol activity?, or is this simply because the film is much more susceptible to determination of Amidol activity?, or... are you wanting to arrive at a new film developer based on Amidol? Thanks again for your continued service...
    Hi Don, I used film as an activity/no-activity test article because it was convenient - it's what was immediately available in the lab I was using.

    My Amidol interest at this point is in the development of Azo contact prints - not film.

    My observation (today) that the developer produced substantial visible stain on the piece of test film led me to check it out with the densitometer.
    Tom Hoskinson
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    Everything is analog - even digital :D

  6. #6
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    <smartass> Darn, I was looking forward to developing my film in Amidol and souping my prints in Don's Pyro. Much easier than doing my film in pyro and my prints in Amidol... </smartass>
    hi!

  7. #7

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    Hey Brian!
    What started this exercise off was my desire to perform comparative tests between Amidol, Don's PPPD, Ansco 130 and Phenidone/Ascorbic (Gainer's PC-TEA)on Azo contact prints.

    The Amidol/PG stock solution is because I want to minimize my handling of dry Amidol.

    I need to run a second set of test prints through Don's PPPD (I fouled up the first set) and run an additional set through Michael Smiths's Amidol for comparison.

    Lord only knows where all this will lead... :p
    Tom Hoskinson
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  8. #8
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    Interesting. Did you notice tanning as well as staining? I think amidol is listed among the moderately tanning agents. I'm don't know what other ingredients you added, but would assume sulfite to be among them.
    Color is sometimes dependent on grain thorugh diffraction as well as staining. Could that be a factor?
    Gadget Gainer

  9. #9

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    Quote Originally Posted by gainer
    Interesting. Did you notice tanning as well as staining? I think amidol is listed among the moderately tanning agents. I'm don't know what other ingredients you added, but would assume sulfite to be among them.
    Color is sometimes dependent on grain thorugh diffraction as well as staining. Could that be a factor?
    Hi Pat,
    The basic formulation is Michael Smith's Azo contact paper developer formulation, so: 30 grams/liter sodium sulfite, 3 grams/liter citric acid, 2ml 10% KBr/liter. The Azo recipe calls for 8 grams/liter Amidol. I just poured in a small dollop (maybe 3 ml) of my ~ 4% Amidol/PG stock solution. The rest of the chemistry is faithful to the proportions in Michael Smith's formulation.

    Since the test pieces of film are uniformly exposed to diffused light (thus no coherent image) it is difficult to judge if tanning or proportional staining is taking place. There is definitely blackened silver plus a dark olive green stain. I'll take a look with a microscope and see what else I can see.

    BTW I developed a second test piece of film this evening when the solution was 8 hours old and saw no difference in activity. I fixed this piece in home brew Kodak F - 24 non-hardening fixer. The stain was very uniform this time.

    I am tempted to try a roll of Efke 100 with real images. That should make it much easier to determine if tanning and/or proportional staining is happening.

    Hey! Did I just step out onto a slippery slope?
    Tom Hoskinson
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    Everything is analog - even digital :D

  10. #10
    juan's Avatar
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    Here's an article on Amidol as a film developer.

    http://simmonsphotos.com/Articles/AmidolFilm.html

    juan

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