Judy Seigel (jseigel@panix.com)
Sat, 16 Jan 1999 14:24:26 -0500 (EST)
On Thu, 14 Jan 1999, Joao Ribeiro wrote:
> Hi,
> I saw somewhere that this salt exists in a brown and green form and
> that the green one is better for photographic use. Why are they
> different and in what way the green one is better?
> TIA
> Joao
>
Joao, no one seems to have answered this on the list, although there is a
thread on it somewhere in the archive. The brown form was the original,
the green form wasn't readily available until maybe 1900 & then was quite
expensive. I don't know the other properties, but the green has come to be
standard for cyanotype, perhaps because it is certainly faster. I know
that the brown is still available because when the chem prof at school
borrowed mine he replaced it with brown, which I returned to him with
suitable protestations.
Now I trust someone will fill in for my deficiencies with more precise
information...
Judy
This archive was generated by hypermail 2.0b3 on Sat Nov 06 1999 - 10:06:42