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  1. #1
    Cor
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    PyrocatMC stock turned light brown

    I hijacked below message from another thread, I have a similair (I think) experience. One year ago I mixed a small batch of PyrocatMC in glycol. Since I had quite some PyrocatHD, I did use the MC stock again only last week, The stock had turned lightbrown. Is this normal? I did process some film with it, these seem to be ok, although one sheet was a bit thin, but that might have been an exposure issue,

    Thanks,

    Cor

    Quote Originally Posted by hka View Post
    My stock solution of Metol has changed color and is now like (coffee) brown. I was mixing a new badge of developer and saw that the Metol solution was a little thick but nearly transparant with some colorisation at the top of the liquid. I put the bottle in some warm water and after a while the color changed to brown. I made this stock solution in mid December last year. Is this a sign that the solution is gone?

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    Quote Originally Posted by Cor View Post
    I hijacked below message from another thread, I have a similair (I think) experience. One year ago I mixed a small batch of PyrocatMC in glycol. Since I had quite some PyrocatHD, I did use the MC stock again only last week, The stock had turned lightbrown. Is this normal? I did process some film with it, these seem to be ok, although one sheet was a bit thin, but that might have been an exposure issue,

    Thanks,

    Cor
    This is normal. The MC stock A solution will turn brown, or sometimes red, after a few months of storage. This does not affects its developing characteristics. I don't know why the color changes with MC. Pat Gainer suggested, or so I recall, that some of the changes we see in mixing solutions in glycol is from food dyes.

    Pyrocat-HD mixed in glycol remains very clear, even a year or more after mixing.

    Sandy King

  3. #3
    Cor
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    Quote Originally Posted by sanking View Post
    This is normal. The MC stock A solution will turn brown, or sometimes red, after a few months of storage. This does not affects its developing characteristics. I don't know why the color changes with MC. Pat Gainer suggested, or so I recall, that some of the changes we see in mixing solutions in glycol is from food dyes.

    Pyrocat-HD mixed in glycol remains very clear, even a year or more after mixing.

    Sandy King
    Thanks for the fast feed back and the peace of mind! Although my negatives were alright , was a bit worried about the colour change! (esp. as you say that PyrocatHD stays very clear in glycol)

    Thanks again & best,

    Cor
    Last edited by Cor; 02-22-2008 at 08:03 AM. Click to view previous post history.

  4. #4
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    I think oxidation of a very small amount of pyrocatechin will cause a lot of color. The same goes for the paraminophenol of Rodinal, which after years of storage is quite potent, but also quite dark. You could dissolve a pinch of pyrocatechin in a liter of water and watch the color change over time. Hydroquinone will do the same. Metol is also quite colorful. If there is any doubt you can do a simple snip test with a piece of exposed film. Even if you don't use 35 mm, you could keep a roll on hand for such tests. If you do a snip test when the developer is new, you will have a sample to compare with later tests.
    Gadget Gainer

  5. #5
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    I've had some of my pyro-metol TEA formula turn a light green with time. There is no loss of potency or development action that I can see.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  6. #6

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    p-Aminophenol was used in hair dye, as was pyrogallol. The former is banned in Europe now for this purpose.

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    I have had some Pcat-P for about 8 mo, about 200 left out of 1000ml container . Mixed with tap water. ( you can get away with that in the northwest ) It is a little brown, but still works OK. I did notice last time that it did not turn quite as dark with the purple. It will take on an amber color after a little while which is normal. I have used the developer after letting it set for almost an hour and still worked OK. Not a recommendation though.



 

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