Re: Blue-Black Cyanotype & Luster

Hello Mark,

a report would be great. Esp. how toning after an acidic bath works for you in comparison to the "normal" procedure.

I´m more and more convinced that the alkali not only converts the prussian blue into ferric hydroxide but also is a kind of activator for the tannic/gallic acid. That could be one explanation for Judy´s (understandable) suspicion about a lot of recipes even if they were not simply copied over and over again. They may have worked one time or another but for consistancy starting point and end point of the reactions must be fixed. And that is not the case if a cyanotype is toned in a tannic/gallic acid bath with an unknown state of activity that continues to tone till the print is dry.

Have a nice day
  Kai Hamann
Received on Wed Oct 5 11:05:07 2005