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  1. #41
    Ian Grant's Avatar
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    Now found references to 3 suggested adjuvants all of which should be better at producing Blue tones than Benztriazole, one is a halide , plus a variable Purple-black, Blue-black, Blue, Violet formula which I'll test in the next few days. Much work was done in this field in the 20's & 30's.

    Ian

  2. #42

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    Quote Originally Posted by Ian Grant View Post
    plus a variable Purple-black, Blue-black, Blue, Violet formula which I'll test in the next few days.
    That sounds extremely interesting, please post your results!

  3. #43
    Ian Grant's Avatar
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    Additive-X

    Quote Originally Posted by thmm View Post
    That sounds extremely interesting, please post your results!
    I did a crude test last night with some Ilford Warmtone FB and the difference in colour was quite distinct.



    The left side was developed in the PQ version of ID-20 (Forte FD-203 which is ID-62 with no benzotriazole), the right with the same developer with Additive-X.

    However Additive-X which is Thiourea (Thiocarbamide) is problematic, the idea is attributed to S.H. Wratten (1910). The Thiourea causes fogging so the developer needs to be well restrained.

    So 10ml of 1% Thiourea in 400ml working solution of developer resulted in almost instant fogging. Cutting the amount of Thiourea drastically adding 10ml of a 0.005% solution and 100ml of 1% Benzotriazole as the anti-foggant gave the results above. The colour shift was caused by the Thiourea, I tried first with no Bezotriazole) which I added to cut the slight base fog.

    This initial crude test shows there's definitely some potential in adding Thiourea, but more work needs to be done.

    Another chemical suggested by I.G. Farbenindustrie (Agfa) to produce cold blue tones is Sodium Fluoride, at 0.4% in the developer formula, but as fluoride is classed as a Poison it's probably got to be ruled out.

    More usually organic compounds have been used, mostly proprietary, starting with quinine hydrochloride, quinoline is said to be amongst the best but has a strong unpleasant smell. Agfa and Ilford Patents show their searches for alternatives.

    Ian
    Last edited by Ian Grant; 04-14-2009 at 07:15 AM. Click to view previous post history. Reason: add

  4. #44

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    Thanks Ian, that is a great test and demo.

    Mike

  5. #45

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    Peoples -

    Do not allow thiourea to come in contact with your skin. See:
    http://www.jtbaker.com/msds/englishhtml/t3107.htm

    Health Rating: 2 - Moderate (Poison)
    Flammability Rating: 1 - Slight
    Reactivity Rating: 1 - Slight
    Contact Rating: 3 - Severe (Life)
    Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES

    "Investigated as a tumorigen, mutagen, reproductive effector."

    It also says it is an anticipated carcinogen.

    You can get cold tones similar to Ian's example using Ansco 130 with benzotriazole substituted for the bromide.
    Also, benzotriazole is not known or suspected as a carcinogen, it has a Health Rating of 1, and a Contact Rating of 2. Much safer than thiourea...
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  6. #46

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    Quote Originally Posted by Ian Grant View Post
    However Additive-X which is Thiourea (Thiocarbamide) is problematic, the idea is attributed to S.H. Wratten (1910). The Thiourea causes fogging so the developer needs to be well restrained.

    So 10ml of 1% Thiourea in 400ml working solution of developer resulted in almost instant fogging. Cutting the amount of Thiourea drastically adding 10ml of a 0.005% solution and 100ml of 1% Benzotriazole as the anti-foggant gave the results above. The colour shift was caused by the Thiourea, I tried first with no Bezotriazole) which I added to cut the slight base fog.
    Hmm, that's very interesting! My uneducated guess would have been that thiourea would be very hard to restrain.
    I suppose such a formulation would be a one-shot developer and sulfide toner (certainly convenient!), or is something entirely different going on here?

    Quote Originally Posted by Ian Grant View Post
    Another chemical suggested by I.G. Farbenindustrie (Agfa) to produce cold blue tones is Sodium Fluoride, at 0.4% in the developer formula, but as fluoride is classed as a Poison it's probably got to be ruled out.
    Well, my toothpaste contains a third of that amount, just for comparison. But of course, getting the fluoride would be hard for mere hobbyists like me...

    Quote Originally Posted by Ian Grant View Post
    More usually organic compounds have been used, mostly proprietary, starting with quinine hydrochloride, quinoline is said to be amongst the best but has a strong unpleasant smell. Agfa and Ilford Patents show their searches for alternatives.
    Hmm, quinine HCl would even be available from chemist's shops over here...

    Very interesting, thanks for posting your research!
    Last edited by thmm; 04-14-2009 at 10:49 AM. Click to view previous post history. Reason: add a detail

  7. #47
    Ian Grant's Avatar
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    Quote Originally Posted by Kirk Keyes View Post
    Peoples -

    Do not allow thiourea to come in contact with your skin. See:
    http://www.jtbaker.com/msds/englishhtml/t3107.htm

    Health Rating: 2 - Moderate (Poison)
    Flammability Rating: 1 - Slight
    Reactivity Rating: 1 - Slight
    Contact Rating: 3 - Severe (Life)
    Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES

    "Investigated as a tumorigen, mutagen, reproductive effector."

    It also says it is an anticipated carcinogen.

    You can get cold tones similar to Ian's example using Ansco 130 with benzotriazole substituted for the bromide.
    Also, benzotriazole is not known or suspected as a carcinogen, it has a Health Rating of 1, and a Contact Rating of 2. Much safer than thiourea...
    Kirk, most chemicals used in Photography are hazardous if used incorrectly, many far more so than Thiourea. The level of Thiourea used is extremely low and so not a potential problem, a great many photographers will be using Thiourea at far higher concentration in Sepia toners.

    Agfa Ansco 130 isn't really a substitute to get Blue/Black tones, and anyway Glycin isn't available in the UK and EU and hasn't been for a number of years, so it needs another approach.

    Quote Originally Posted by thmm View Post
    Hmm, that's very interesting! My uneducated guess would have been that thiourea would be very hard to restrain.
    I suppose such a formulation would be a one-shot developer and sulfide toner (certainly convenient!), or is something entirely different going on here?
    Something different is definitely going on, you'd expect Thiourea to give warmer tones but it's doing just the opposite.

    Ian

  8. #48

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    Quote Originally Posted by Ian Grant View Post
    Agfa Ansco 130 isn't really a substitute to get Blue/Black tones, and anyway Glycin isn't available in the UK and EU and hasn't been for a number of years, so it need[s another approach.
    It is available from a company called Fototechnik Suvatlar via Wolfgang Moersch (see http://www.moersch-photochemie.de/content/rohchemie, sorry, only in german). Just in case someone is looking for it...

    Quote Originally Posted by Ian Grant View Post
    Something different is definitely going on, you'd expect Thiourea to give warmer tones but it's doing just the opposite.
    Hmm, I have seen warm tone papers get colder (violet-brownish) in sulfide, and assumed that was what had happened there. Very interesting!

  9. #49

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    Quote Originally Posted by Ian Grant View Post
    Kirk, most chemicals used in Photography are hazardous if used incorrectly, many far more so than Thiourea.
    Something is "hazardous" regardless of how it's used. It's an intrinsic property of the substance. The amout of risk or exposure varies based on the practice of the individual using it.

    I just want to point out that thiourea is a suspected carcinogen (unlike the vast majority of photochemicals typically used in the home darkroom) and people should be aware of it.

    That said, I've used thiourea toner myself, so I'm not saying it's something to never use, I'm just saying it's something that people need to have some understanding of the potential hazards when using thiourea.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  10. #50

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    Quote Originally Posted by Ian Grant View Post
    Agfa Ansco 130 isn't really a substitute to get Blue/Black tones,
    The benzotriazole variation of Ansco 130 that I mentioned above certainly does change the tone of Ilford Warmtone FB paper, and much as you show in your scans above. No thiourea needed to make a nearly neutral paper considering how warm it is to start with.

    Could you take some color densitometer readings of some paper in your formula at Dmax and compare them to the same paper in regular developer so we can get an idea of the color shift?
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

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