Liam Lawless (lawless@vignette.freeserve.co.uk)
Sun, 30 May 1999 23:02:58 +0100
Hi,
Not too sure about this one, but something you might like to try. If it's a
blue stain you're talking about, it's ferric ferrocyanide or Prussian blue,
and treating this with an alkali will bleach it to a colourless compound,
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.
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
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:35