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  1. #1

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    Combining benzotriazole and bromide

    Hello,

    I am just starting to experiment with a fridge full of old paper that was "given" to me for $20.00. Lots of old Ilfochrome paper, lots of old black and white, some of it expired in the '40s, most expired in '50s-'70s.

    A lot of the paper prints fine in the black and such, but, as expected, is fogged in the highlights. The tonality is great, but I am looking to clear the fog a bit.

    I have used Kodak Anti-Fog tablets several times on old film, and it helped. I know they don't have these any more, but they used to have several versions; some for film, some for paper, etc.

    I have read on this forum that both benzotriazole and potassium bromide can have anti-fog effects, but work in different ways, and cause cool and warm tones, respectively.

    My question is: what happens when you mix them? To try this, how much should I use? My developer is Ilford MG, and I usually use two liters at a time. Will anti-fogging agents work in a diluted A+B litho developer, or will the long developing times pretty much make them useless?

    Thank you in advance.
    Last edited by 2F/2F; 05-17-2008 at 07:15 AM. Click to view previous post history.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  2. #2

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    my paper in rol, i have to trim it, it seem my safelight too bright, so got fog in my Ilford MG, i try a few Bzt n bromide alone n several combinations but couldnt get rid grey in highlight, i read at silvegrain, that's true nothing we can do with paper fog http://silvergrain.org/wiki/Fogged_Paper

  3. #3
    Ian Grant's Avatar
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    In some dev formulae both are used, particularly Ilford PQ paper developers that were the PQ variants of older MQ formulae.

    These PQ type developers tend to be cleaner working, less prone to base fog anyway, so if you can use one rather than something like Dektol/D72 and add additional Benzotriazole & KBr that will help and also boost the overall contrast slightly.

    There's definitely no problem adding both.

    Ian

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    [QUOTE=....... and add additional Benzotriazole & KBr that will help and also boost the overall contrast slightly.

    There's definitely no problem adding both.

    Ian[/QUOTE]


    that's true Ian, for fresh paper, i used them both, cut the bromide to 1/3 and add Benzotriazole 25ml 1% solutions per liter get good highlight, in my eyes better than if i used it bromide or Benzotriazole alone

  5. #5
    Ian Grant's Avatar
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    With a PQ developer if you use KBr alone you get warmer tones, Benzotriazole alone colder tones. PQ developers are inherently slightly warmer than the equivalent MQ version. This is why both are normally used to give relatively neutral tones.

    If it was an aerial fogging question then adding Sodium or Potassium Metabisulphite is highly beneficial, and works exceptionally well.

    Ian

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    Quote Originally Posted by Ian Grant View Post
    PQ developers are inherently slightly warmer than the equivalent MQ version.

    Ian
    I thought it was the other way around.


    Wayne

  7. #7
    Ian Grant's Avatar
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    Quote Originally Posted by Wayne View Post
    I thought it was the other way around.
    Wayne
    Yes that's right in one respect, but that's because of the addition of Benzotriazole to control the tones.

    A typical example is Ilford ID-20, ID-62 & ID-78

    All have

    Hydroquinone 12g
    Sodium Sulphite 50g
    Potassium Carbonate 60g (ID-78 62g)

    plus

    ID-20
    Metol 3g
    Potassium Bromide 2g

    ID-62
    Phenidone 0.5g
    Potassium Bromide 2g
    Benzotriazole 20ml (1% soln)

    ID-78 Warm Tone Developer
    Phenidone 0.5g
    Potassium Bromide 4.5g

    There's also a variant of ID-62 published with no Benzotriazole, this gives slightly warmer tones than ID-62 or ID-20

    Essentially ID-62 and ID-78 are just PQ variants of the much older Ilford ID-20 formula. To achieve neutral tones with a PQ developer you must add Benzotriazole.

    Ian

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    Quote Originally Posted by Ian Grant View Post
    Yes that's right in one respect, but that's because of the addition of Benzotriazole to control the tones.
    I thought the benzotriazole was there because phenidone is not very sensitive to the restraining action of kbr, not to control the tone.

  9. #9
    Ian Grant's Avatar
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    Wayne, I have the 1954 article where Ilford describe varios Phenidone developers, they had only begun commercial production of Phenidone a couple of years before. This is what Ilford said:

    "For high speed negative materials which tend to run into fog, particularly with forced development, the addition of an organic antifogging agent is an advantage although this is unnecessary where the developer has been buffered to have a pH of less than 9 at working strength. The type of antifogging agent and the concentration employed is a matter of choice depending upon the type of material to be developed and the characteristics required. Benzotriazole, for example, is particularly useful for universal and contact paper developers, since it also has the effect of modifying the tone of the silver image so that this becomes the cold blue-black which is generally considered desirable with contact prints. With developers used for negative materials, other fog restrainers which do not influence the colour of the image can be employed. It should be remembered, however, that too liberal use of any antifogging agent can result in a slowing of development, a drop in speed and a loss in the maximum density of the silver image, so that additions should not exceed those recommended for a particular purpose by the suppliers."

    Most published lford PQ developer for papers are generally Universal type developers, so contain Benzotriazole, the exception is ID-78 the warm tone developer.

    None of the published Ilford PQ film developers contain Benzotriazole.

    Ian

  10. #10

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    Thanks Ian.

    So, what would be a good PQ developer to use? Right now I use Ilford Multigrade, and I don't know what type of developer it is. Do I need something else (like Ilford PQ, perhaps )?
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

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