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  1. #11
    jnanian's Avatar
    Join Date
    Jun 2003
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    Quote Originally Posted by Keith Tapscott.
    This all depends if you want a Metol free developer, if you prefer PQ or have an alergy to Metol, then fine. Some people prefer the tonality of films developed in MQ or Metol based developers.
    keith -

    d-76 and sprint film developer are identical and you will not be able to see the difference between film processed in one or the other.


  2. #12

    Join Date
    Dec 2004
    Multi Format
    Quote Originally Posted by dancqu
    D-76H, is a misnomer. D-23+B would be more accurate; D-23
    with a little borax and one third the metol. Subtract the borax
    as well.

    The very little borax in D-76 serves only to restrain an
    increase in ph. Rather than an unrestrained build up of OH
    radicals, the borax hydrates and metaborate is formed. Although
    the ph still increases it does so at a more moderate rate.

    I did subscribe to another explanation for D-76's ph
    instability. As put forth by Milan Merhar some years ago,
    the slow hydrolysis of the borax is the problem. That sounded
    plausible. But then again why included an ingredient
    which had no purpose but to cause problems? I no
    longer subscribe to Merhar's reasoning.

    Some account for the presence of the borax because it
    works as an activator. That can't be because it amounts
    to only 1/50 part of a substance, sodium sulfite, which has
    a ph a little higher than that of itself.

    I think that borax-metaborate ph control a good reason
    for borax being present WHEN hydroquinone is present.

    Subtract the hydroquinone and the borax, triple the metol
    and call it D-76HB XXX or D-23. Dan
    Everyone seems to have settled on the name D-76H, I assume to connect it with Grant Haist who suggested it.

    Merhar's reasoning is faulty, borax does not hydrolyse and is a stable compound. In fact it is used to make pH standard buffers.

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