[PRCo] Re: FARTHER OFF TOPIC (COLOR FILM PROCESSES)

[hwandrews1 at cs.com]

Fred,

Fred - the process you discribed that you father used was, I think, called tri-color photography.  It is based upon the 3 primary (red, green and blue) colors.  And you right, technicolor was shot on a special camera that did the 3 color seperation in the camera and exposed 3 rolls of B&W film.  When they did the release films the dyes were added based upon the density of the B&W master.

The dye transfer process is a method of printing images.  Kodak use to market everything you needed to do this - but I haven't see it in years.  Basically with Dye Transfer you made 3 gelatin masters, one for each primary color, then 'transfer' subtractive dyes (cyan, magenta and yellow) to the carrier paper.

Today most of the the color film is what's called 'chromagenic' - that is the dyes are formed in the emulsion when the image is developed.  That's why most of them are not archival - i.e., they do fade over time.  The one exception is Kodachrome - it is really a 3 layer B&W film and the dyes are added during processing.  That's way Kodachrome has such rich colors - and is so darn expensive!  It is also the most archival film you can buy.

Had to add my 2 cents - photography is one of my many interests.

Howard
>About color photographic processes:  delete now if uninterested.
>
>Thank you.  Incredibly interesting.   I have a limited working knowledge of contemporary and recent printing ... linotype and zinc plates, photo lithography, rotogravure ... but nothing this old.  Obviously it looks like hand colored cards because the master was hand tinted.
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>Someday before I die I would like to try making a dye transfer print.  The results were always far superior to color printing process except that I think some of the computer work today is as good.  My dad once tried it.  He made a picture of the Pittsburgh house using three separate 6x9 cm negatives, each taken through a red, a
>green, or a blue filter ...  Therefore each represented one of the three colors needed to make a print.  What was unique was his use of filters to take original negatives of the subject (the house), rather than starting with a color image and making three separate back and white negatives from the original slide.  If I'm not
>mistaken (and let's hope I'm not), the Technicolor movie process is similar with dyes being printed on clear film stock (in contrast to Kodacolor, Ektacolor, Eastmancolor, Kodak Gold, etc. in which the dyes are created during a developing process).  Technicolor dyes were much more stable than Eastmancolor (a lower contrast version
>of Kodacolor), therefore the better films of the 1950s and 1960s were done on Technicolor if it was felt up front that the demand would warrant the added cost.  As we well know, movie prints from Eastmancolor, like paper prints from Kodacolor, turned pink in time.
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