Slide duplication

[Seth Baldwin]

How was 35mm slide film like ektachrome typically duplicated in the past for preservation purposes? Did they use color-negative intermediate stock like 2242, a stock designed specifically for slide, or a completely unique process? I'd imagine the gamma wouldn't transfer well over to 2242.

Edited January 16, 2023 by Seth Baldwin

[Frederick Knauf]

Kodak manufactured and sold a product called Kodak Ektachrome Slide Duplicating Film, code 5071 f,or the purpose of making duplicates.  Prior to personal computers and projectors and now large screens tied to a computer, trade shows utilized many sets of slide duplicates for presentations, as well as those who wanted to project presentations while protecting their originals. The film processed in standard E-6 chemistry.

The film featured very clear D-min and very straight curves.  Here is the curve shape attached.   

Motion Picture Color Intermediate Film, code 5242 or 2242, is similar in its flat 1.0 gamma, but the is the issue with the secondary development not necessarily achieving the required reversal faithfully and the inherent base density / masking density.

  

 

[Charles MacDonald]

when large quantities were needed, like to send out slides to every dealer of a product, preparing the slides using Motion Picture materials was also possible.  there was also a Ektacolor Positive film for making slides from a "still" colour negative image.  (still film and Movie film having different contrast ranges)

other makers also had a duplicating reversal film like Ansco 5479.  (don't know why I remember that one) in fact Kodak themselves would make duplicates using a Kodachrome duplicating material.

 

[Frederick Knauf]

Yes, Charles, there were other means of slide duplication involving the use of internegatives and then printing onto Eastman Color Print film.  Slide strips, sold at stores in places like Niagara Falls, Yellowstone, and the Grand Canyon, would use that method.  Kodachrome Duplicating films were also around in 1940 (code 5265) through to 1966 (code 5269) but then duplication for the stills reversal market went to the Ektachrome Duplicating and the 16mm duplicating went to Eastman Reversal Color Print film through to 1981 when that was discontinued due to low sales.  This is all from information from the Professional Films Product Staff passed on to me in the 2010 time-frame when that group was dissolved.