From: martinm (martinm@SoftHome.net)
Date: 07/25/03-12:07:52 AM Z
----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <walker@sympatico.ca>; <alt-photo-process-l@sask.usask.ca>
Sent: Thursday, July 24, 2003 11:28 PM
Subject: Re: Bromo-iodide Silver Gelatin Emulsion as an Alternative process
> > But I take that back, the dyes are mysterious! I have spent about 6
> > months on a Dye called Orthochrome T mentioned in Wall's book. So if
> > you want a challenge we can compare notes...
>
> I don't know Orthochrome T is still in use or available, or
> corresponds to what name in modern nomenclature. It is a primarily
> green sensitizer but posses high orange and red sensitivity, so it is
> considered a panchromatic dye in old literature.
Orthochrome T is 1,1'-diethyl-6.6'-dimethylisocyanine. According to
Glafkidès its absorption peaks are at 530 and 583 nm.
For well balanced panchromatic sensitized emulsions in Lippmann photography,
Neuhauss used cyanine, erythrosin and glycine red.
A more advanced solution would be choosing pinacyanol chloride (red) and
1,1 -diethyl -2,2 cyanine iodide (green). Have a look at
http://cabd0.tripod.com/holograms/id3.html
Since those two dyes cannot be used at the same time, this would imply the
making of two different silver halide solutions, one for each dye.Prior to
coating they would be mixed together...
Martin
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