Re: Restoration of tri-color camera

----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, March 09, 2005 5:25 PM
Subject: Restoration of tri-color camera

> Depending on how you look at it, lucky or damned, I have
> been gifted with a rare 5X7 tri-color camera from the 30s
> or 40s that I hope to restore and use to make real
> in-camera separations. Yes, I know that I can make
> separations from color negatives and color slides, and/or
> directly via the digital mode, but I am really excited
> about making some three-color carbon prints using original
> technology.
>
> Thing is, to restore the camera I will need to acquire a
> new pellicle mirror and filters. Any leads as to where I
> might be able to buy one or both of the above would be
> appreciated.
>
> And thanks in advance.
>
> Sandy
>
   Do you know who made the camera? In the US there were
three main makers, two of whom merged. Devin, National
Photocolor, and Thomas Curtis. Devin and National Photocolor
merged some time around the 1940's. Curtis was here in Los
Angeles.
   It seems to me that Dick Sullivan may have gotten
interested in these things, you might try contacting him. I
am not sure of the exact process used for maiking the
pellicles but I am pretty sure they were gelatin silvered on
one side. The idea of using gelatin is to avoid "color
wedging" from the spherical and chromatic aberration of
light passing through a parallel glass plate at an angle.
Gelatin is both very thin and also lower in index of
refraction than glass both of which contribute to good
performance as a beam splitter. The color filters were
probably standard Wratten color separation sets. There may
also have been some neutral density content since the films
must be exposed and developed so that the characteristics
lie on top of one another.
   Bostick & Sullivan have been working with three color
carbro for a while and I think have suitable materials
available.
   These cameras were driven out of existence by Kodachrome
although some studios continued to use one shot cameras and
color carbro for reproduction originals due to the control
available.
   I think this is a great project.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com