[GreenKeys] Now I know how they work!

[Richard Knoppow]

     Both Technicolor and Kodachrome (second version there was another 
in the 1920s) were capable of very lifelike color but the market wanted 
LOTS of color. Both were without "masking" for correction of imperfect 
dyes but the original Technicolor included a gray or black key so was 
actually a four color process. The history of Technicolor has been well 
recorded, a lot of it is on the web. I had the pleasure of meeting some 
of the technicolor management and scientists at a SMPTE meeting locally 
when the dye imbibition printing process was discontinued.  Technicolor 
killed off despite strong objections from the film industry simply 
because the equipment was wearing out. They had to speed everything up 
to meet competitive costs of multilayer films. I also saw a demonstation 
of their attempt to resurrect it several years ago at the studio theater 
at Fox. Looked awful. The process was at its best IMO in about the early 
  1940s. The dyes used in the prints were far less fugitive than those 
used in multilayer films so many of those original prints still looked 
as good as they did when made up to maybe the 1980s. Of course all were 
on nitrate base so can not be projected any more.
     Kodachrome was a sort of elegant makeshift. Kodak had been trying 
to devise a practical color process from at as far back as the mid teens 
of the  20th century. In fact, the main reason George Eastman hired 
C.E.K. Mees away from the British company Wratten and Wainwright was to 
work on color sensitizing of film. Actually Mees was a partner in W&W so 
Eastman bought the company. Mees agreed on condition that his former 
partners be allowed to remain in management. Mees and Wratten had 
considerable background in dye technology both for sensitizing film and 
for filters. Mees founded Kodak Research Laboratories in 1912, one of 
the first industrial research laboratories anywhere, however, they were 
unable to come up with a good single emulsion film for color. The 
impetus for Kodachrome was the release by AGFA of a practical 
multi-layer film in the mid-1930s. Kodak then came out with Kodachrome 
but it required an extremely complex processing method which could be 
done only at the factory in Rochester, N.Y. Eventually, Kodak found a 
different way to "sequester" the dyes in emulsion layers so was able to 
make a competing film with out infringing on AGFA patents. This was used 
for Ektacolor and Ektachrome and the process could be carried out by any 
competent independent  lab. For many years labs had to be set up for 
both Kodak and AGFA type film but I believe the surviving system is the 
AGFA system.
     Enough of this very off topic stuff. I am writing it because I 
think Greenkeys people are interested in obscure and arcane technology.

On 5/31/2017 9:53 AM, Dave Horsfall wrote:
> On Wed, 31 May 2017, Richard Knoppow wrote:
> 
>> In Dufaycolor yet! See
>>
>> https://en.wikipedia.org/wiki/Dufaycolor
>>
>> for a short article on this interesting color photography system. It
>> even mentions the BT film linked below. Duplicating it is a difficult
>> process.
> 
> Yes, I was astonished when I saw it was in colour.  I was half-thinking of
> Technicolor (whereby colours are really garish, but skin tones tended
> towards the yellow or the green) but I doubted whether it would've gone to
> that extreme.
> 

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL