Re: Prussian (Berlin) Blue vs Turnbull Blue in Cyanotype

I think that the Ware Cyanotype book is the authority on this; I recall
him saying that a finished cyanotype (from a standard a+b formula, or
its derivative) is some combination or other of the ferrous and ferric,
as well as prussian white.
Regardless of whether there are differences in the two blues or not, I
think the final word was that trying to archive a pure prussian blue is
impossible in this formulation (environmental reasons, chemical reasons,
etc.), so if you want one versus the other, there is a lot to contend with.
Perhaps the new process addresses this?

good luck,
Kris

Monnoyer Philippe wrote:

> Hello,
>
> I'd like to try reversal (positive) cyanotype which gives Prussian Blue (ferric ferrocyanide). Before ordering potassium ferrocyanide I would like to ask you guys how Prussian blue compares to the common (negative) cyanotype Turnbull blue (ferrous ferricyanide).
> Is it colder, deeper, ... ?
>
> Thanks,
>
> Philippe
Received on Thu Nov 6 08:28:15 2003