[ARC5] WW II Aircraft factory pictures

[J. Forster]

My belief has always been that Ektachrome was the better film for natural
color rendition. IMO, Kodachrome produced "WHAM, POW, SOCK" cartoon-like
images.

YMMV.

-John

======================



>
> ----- Original Message -----
> From: "Bob Macklin" <macklinbob at msn.com>
> To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>;
> <jfor at quikus.com>; "Christopher Bowne" <aj1g at sbcglobal.net>
> Cc: <arc5 at mailman.qth.net>; "Clare Owens"
> <clare.owens at gmail.com>
> Sent: Sunday, February 17, 2013 9:48 AM
> Subject: Re: [ARC5] WW II Aircraft factory pictures
>
>
>> My memory of Kodachrome says that Kodachrome was only
>> processed by Kodak labs?
>>
>> I have been using Exctachrome for slides for may years.
>> Still have 6 rolls in the fridge.
>>
>> Bob Macklin
>> K5MYJ
>> Seattle, Wa.
>
>      Kodak originally processed Kodachrome only at the
> factory at Rochester, N.Y. After about a year a simpler
> method of processing was devised and Kodak established
> processing stations in other cities.  I think eventually
> there were about four.  Sometime in the 1960s (by memory)
> Kodak was sued for restraint of trade because they included
> the cost of processing in the price of the film. They had to
> stop this practice but at about the same time begain to
> license independant laboratories to process Kodachrome.
> Kodak supplied the machinery and chemistry since, even with
> simplification of the original proces, it was still complex
> and difficult to control.  Kodak had a vested interest in
> maintaining the quality of the results so was pretty careful
> about the independant processors.  Kodak also continued to
> process the film in their own labs.
>      Kodachrome is a three layer film but the "couplers" or
> dye intermediate chemicals are not included in the layers.
> This was because Kodak could not find a way of
> "sequestering"  them to keep them from wandering into the
> wrong layer.  So, the couplers were put into the reversal
> developers.  The film was developed to black and white
> silver images in all three layers then re-developed in three
> separate reversal baths to generate the color, the silver
> being removed after processing.  It was the method of
> insuring the right color would appear in the right layer
> which was changed from the early to the later processing
> method.  The original method, which  I beleive was used only
> for about a year, required the controlled penetration of a
> bleach into the developed film.  After the initial B&W
> processing the film was developed again in a bath with the
> coupler for the bottom layer, this produced color dyes in
> all three layers. It was then floated on a bleach bath which
> bleached the color out of the top two layers then developed
> again in a bath with the coupler for the center layer. Then
> the top layer was bleached out and developed with the proper
> coupler for the color there. In between these steps the film
> was washed and _dried_. The drying was done to control the
> rate of up take of the bleach bath.  After about a year
> another method was devised; this one used differential
> re-exposure and made use of the remaining color sensitiivty
> of the layers.  It still took three re-development baths but
> the bleach steps were eliminated.  After this method as
> adopted Kodachrome became available in many formats other
> than 16 mm film.  Up to about 1948, when Ektachrome was
> announced, Kodachrome was made in sheet sized up to 16x20
> inches!  All the larger films were processed in Rochester.
> Commercial and advertising photographers who had come to
> rely on Kodacrhome were very upset at its discontinuance in
> sheet sizes because Ektachrome was thoroughly inferior.
> Ektachrome had the advantage that any commercial lab could
> ste up to process it although it was still quite fussy.
>      Kodak had discovered a method of sequestering the
> couplers in the early 1940s which was used first for
> Kodacolor and its print paper. The color was inferior to
> Kodachrome but the processing was much easier.  At about the
> same time as Kodachrome was announced AGFA had come up with
> a multiple layer color film but using incorporated couplers.
> They had come up with a different method of sequestering the
> couplers than Kodak used.  Agfacolor was not sold outside of
> Germany and most seems to have been used by the government.
>      Both methods of sequestering the couplers continued to
> be used for decades, I am not sure which method survives.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com
>
>