Analyzing Namias's Approach to Using Rosin

[John Grocott <john.grocott403@ntlworld.com>]

Alberto,
              From your outline it is obvious that Namias worked with 
Bromoil. This means that he used  bromide paper to make the matrix OR was he 
using his own gelatine coated paper which would suggest that he was, in 
fact, doing Oil Printing.
               Having tried Bromoil I understand that Rosin may be used to 
stiffen up the ink.  But his experiments must have led him away from  oil 
based ink to arrive at what we now accept as a  Resinotype powder 
application.  Quite different to Bromoil.
              More later. John-Photographist - London - UK
----- Original Message ----- 
From: "Alberto Novo" <alt_list@albertonovo.it>
To: <alt-photo-process-l@usask.ca>
Sent: Saturday, November 03, 2007 7:11 AM
Subject: Re: Rosinotypes without Rosin ?


> > Could you  please remind us why it was that Rodolfo Namias decided to mix 
> > rosin with pigments rather than simply using just pigments. Something to 
> > do with stabilizing the powder in the gelatine?
> > Using fixed out bromide paper, washed, dried and sensitized I have used 
> > only pigment powders brushed onto the swollen matrix with some success.
> Pure pigments perhaps may work on photographic paper, but if you use them 
> directly on gelatine you obtain a muddy print. The rosin (but nowadays we 
> might use any other more modern hydrophobic substance) helps to 
> differentiate the sticking of the powder to the (more) wet areas, where 
> the gelatine has not been hardened by light+dichromate, and the (less) wet 
> areas where the gelatine has been hardened. Rosin is simply one among the 
> cheaper substances you can use.
> Namias wrote that he had his idea because, working on a bromoil with an 
> ink made too stiffen with rosin and pigment, he obtained a reversed image. 
> In fact, this is also the matter of his patent.
> Alberto