[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: brown ferric ammonium citrate





On Tue, 25 Jul 2000, nze christian wrote:

> here are the difference between brown and green ferric citrate ammonium
> the green one contain 14 % of iron and brown 22%
> brown weight / mole 615
> green weight / mole 733
> 
> and green is  little acid and brown a little basic
> 


for what it's worth, I cam across in my files a note that Mike Ware said
that Eder said that brown was "8 times slower" than green. But also, for
what it's worth, until about 1900, the green wasn't available, so all
those beautiful 19th century blues were made with brown, well not all,
because some used other compounds, but you know what I mean.

In fact the chemistry professor at school. as recently as 15 years ago,
taught his students cyanotype with brown. One year he borrowed my green in
an emergency then returned it with brown. I freaked -- what did I know
about brown? OK, OK, he ordered some green, but I think that was the first
he'd heard of it.

Judy