Judy Seigel (jseigel@panix.com)
Sun, 30 May 1999 22:15:44 -0400 (EDT)
On Sun, 30 May 1999, Liam Lawless wrote:
> ferrous hydroxide. This is what you probably got after using lemon ammonia,
> but it's insoluble and I would guess that it's reacting with something in
> the carpet to re-form Prussian blue. An acidified solution of pot.
> ferricyanide is one such "something", not that I'm suggesting that's in your
> carpet, but other chemicals - the sort they make carpets out of - might be
> present.
I think Liam's point that there may be some other chemicals in the carpet
that interfere is well taken... but my first thought was -- *lemon*
ammonia? What is that, a cocktail? I've taken cyano stains out of plain
fabric with borax, 20-Mule team, and/or washing soda (sodium carbonate). I
think maybe lemon ammonia is very adulterated, or who knows? However, as
I recall, once it's bleached you have to do something to remove the
residual, as Liam says. My fabric could be washed & that did it, though a
carpet probably not the same way. (However, rest assured -- if you WANTED
the tone to return, as in toning cyanotypes, it would vanish forever.)
> Anyway, my suggestion is to try bleaching the blue with an alkali again,
> then (after washing) treat the area with an ordinary print fixer which I
> think will clear the ferrous hydroxide. If this fails, try again with
> citric acid, dilute HCl, EDTA Na4, or any of the others used for clearing
> iron from platinum prints.
>
>
>
> Liam
>
>
>
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