[ARC5] WW II Aircraft factory pictures

[J. Forster]

Whatever they were, the comparison of Kodachrome/Ektacrome stands.

-John

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


> Ever  seen  color  pictures BEFORE Kodak ?
> Gd
> ----- Original Message -----
> From: "J. Forster" <jfor at quikus.com>
> To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
> Cc: "Clare Owens" <clare.owens at gmail.com>; <arc5 at mailman.qth.net>
> Sent: Sunday, February 17, 2013 12:00 PM
> Subject: Re: [ARC5] WW II Aircraft factory pictures
>
>
>> 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
>>>
>>>
>>
>>
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