[alt-photo] Re: Tri color photos Russia

[Richard Knoppow]

----- Original Message ----- 
From: "phritz phantom" <phritz-phantom at web.de>
To: <alt-photo-process-list at lists.altphotolist.org>
Sent: Monday, August 30, 2010 2:28 PM
Subject: [alt-photo] Re: Tri color photos Russia


>  Am 29.08.2010 21:42, schrieb Richard Knoppow:
>>    I believe the original pictures were intended for 
>> projection.
>>
> i think there is proof for that in the pictures. in pic 27 
> the child on the far left moved its head during exposure. 
> one can clearly see the red and green exposures and the 
> blue one too a little. and only where all three colors 
> overlap, the head (with some kind of baby hat on) has the 
> correct white color.
> at first this totally baffled me, because i thought in 
> prints it's always the additive method of color mixing 
> that is used. but if those pics were intended for 
> projection, it makes sense that the subtractive method is 
> used. or doesn't it?
>
> please, experts, correct me, if i drew the wrong 
> conclusions here.
>
> phritz

    While this is answered on the LOC site a direct answer 
might be in order. Color by projection can be either by 
subtractive or additive process. Additive is very simple, 
three positives, each for a primary color are projected 
through three projectors each with the appropriate color 
filter. For subtractive color the light must pass throug 
three transparencies sequentially, each removes some part of 
the spectrum of the white ligh, hense the name subtractive. 
The three transparencies must be in intimate contact. Each 
is colored with a dye in the compliment of the color it 
represents. Thus the Green transparency is dyed magenta. 
Modern color films are all subtractive and all have all 
three color layers coated on the same film, one on top of 
the other. Additive color transparencies for simultaneous 
projection could be made from these but this is not very 
often done.
    A number of schemes have been developed historically for 
making additive color on a single film. These range from 
exposing multiple frames on one film to various kinds of 
built-in filters. The most common filter type films used 
either a distribution of dyed particals, often starch, 
coated on top of or under the emulsion, or a network of 
colored lines printed on the film or glass support just 
under the emulsion. The colored material remained throughout 
processing and was used to color the light during 
projection. Prints and duplicates could be made from these 
films but was difficult, especially duplicating since the 
colored particals or lines had to exactly match. This is the 
reason none of these processes was successful for 
professional motion pictures where many prints must be made. 
However, where the original film is developed by reversal 
and used for projection they work pretty well and some films 
of this type were available for home movies.
     The puzzle about Gorskii's process is the design of the 
camera. While it obviously took sequential frames they must 
have been taken in a very short time. There is some evidence 
of subject movement bewteen frames but its slight and shows 
up only where the movment must have been rapid.

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