[rollei_list] Re: B&W film developing
- From: Chris Burck <chris.burck@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 13 May 2014 14:58:42 -0500
Fascinating. Can't help but wonder what would have been, had Kodak been
unable to breach Agfa's patents.
On May 12, 2014 11:52 PM, "Richard Knoppow" <dickburk@xxxxxxxxxxxxx> wrote:
>
> ----- Original Message ----- From: "Eric Goldstein" <egoldste@xxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Monday, May 12, 2014 2:20 PM
> Subject: [rollei_list] Re: B&W film developing
>
>
> >
>>
>>> > Kodak adopted a system that is in some ways opposite > of the Zone
>>> system. What Kodak recommended was to expose to get the information on
>>> the
>>> film and develop for a desired gamma or contrast index, then adjust the
>>> contrast of the image by choice of paper grade.
>>>
>>
>>
>>
>> Richard, I don't think it's accurate to say what Kodak recommended was the
>> opposite of the Zone system. First and foremost, the zone system does not
>> recommend an exposure that would not result in getting the desired
>> contrast
>> on the film, so in that sense they are both saying the same thing.
>>
>> What always struct me as a contradiction to the statement "What Kodak
>> recommended was to expose to get the information on the film" was their
>> rating of consumer Tri-X as an ASA 400 film. In the strict sense of the
>> then-new ASA definition, it may have been, but I think most folks who shot
>> it regarded it and treated it as a 200 speed film exactly in the spirit of
>> exposing to get the information on the film.
>>
>>
>> Eric Goldstein
>>
>
> I think the difference is that the Kodak method was to make the
> contrast adjustments in printing and the zone system to make it in the
> negative. Actually you need to do both and some scenes will need individual
> manipulation i.e. burning and dodging, to get the image right. Either
> system will get you there if you understand what you are doing. Kodak was
> more interested in the mass market and minimal manipulation of negatives.
> Print contrast via different grades of paper can be done in mass production
> printing, that is, photo-finishing.
> The published speed for Tri-X or any other film is the result of
> measuring it via some speed determining method. I don't remember now how
> Jones specified exposure and density ranges other than the speed point was
> where the toe gamma was 1/3rd of the straight line gamma. There is a
> problem with this since many films do not have a truly straight line part
> of the curve. I think average gamma may have been used. This measurement is
> a difficult one to make so the system was abandoned when it was discovered
> that a minimum density speed point with a correction would usually
> duplicate it. Now, film is used in practice in ways different from the way
> the film speed measurement uses it. Remember that Jones found that an
> increase in exposure of many stops did no damage to the tone rendition. So
> some increase in exposure is perfectly satisfactory especially if one is
> not quite certain about the accuracy of exposure of the camera (usually
> they overexpose but not always). The main drawback of increased exposure
> is increased printing time, not a big deal. My own experience is that most
> films give better images when given a bit more exposure than the box speed
> suggests. There really is no such thing as "true" speed, there is measured
> speed, that is measured using a controlled system which is reproducible and
> there is whatever speed results in the most pleasing prints. Maybe not
> always the same. Actually L.A.Jones was trying for the latter in his
> experiments. Unfortunately, the papers are scattered. Many are in the
> Journal of the Franklin Institute but some are elsewhere. There are
> references in Kenneth Meese books. Mine are stashed away at the moment. Its
> possible some of this is available from the web but I was never able to
> find any of it and my copies of Jones papers are all from the public
> library.
> A note: When Meese created the Kodak Research Laboratory he decided
> that the scientists at Kodak should publish their scientific papers in
> established, peer-reviewed, journals rather than in a house organ of some
> sort. This gave to Kodak immediate credibility and status. However, it may
> make some materials difficult to find because one must search many
> journals. OTOH, it is very difficult to find some company published
> journals. I found Meese's "Theory of the Photographic Process" on Google
> books, well worth the download even though chemical theory has changed
> substantially since it was written. Meese has an extensive bibliography of
> earlier research including Jones's work. BTW, the spelling of Loyd is
> correct.
> You may all be aware that Meese was working for and a part owner of
> Wratten and Wainright in England. W&W had done very considerable research
> into the use of dyes for sensitizing film as well as for filters. George
> Eastman, who had a tremendous respect for British scientists, was already
> interested in developing a practical method of color photography and wanted
> Meese partly to aid in that project. Meese told Eastman that he was willing
> to go to Rochester provided that Eastman would buy out Wratten and leave
> the founders in charge of it. Eastman agreed and W&W became a part of
> Kodak. Meese came to Rochester and set up the Kodak Research Laboratories,
> one of the first corporate research laboratories in the US. It was partly
> modeled on the laboratories at General Electric which were the successors
> to Edison's labs and the lab at Western Electric which later became Bell
> Laboratories, . This was in 1912 which was a very important time for
> industrial research, the labs at GE and WE made discoveries at about this
> time that allowed perfecting the vacuum tube and resulted in the enormous
> growth of electronics. Meese was not able to devise a practical color
> photography method for decades. Eventually AGFA came up with the "modern"
> type of color, that is a multi-layer film with built in color couplers so
> that it could be developed directly into a color image. Kodak eventually
> found another way to achieve this but it was not fundamentally different
> from the AGFA method. Kodachrome, despite its great success, was really
> only a stop-gap since it required a very complex processing method well
> beyond what could be done by most commercial labs let alone the amateur
> photographer. Kodak had a couple of earlier processes, both using names
> that got re-used later: Kodacolor and Kodachrome. One was an additive
> process using particles of dyed starch (or maybe a reseau, I don't remember
> at the moment) the other a lenticular process which was used for color
> motion pictures. Neither was very satisfactory or very successful.
> I have run way off the topic and will stop now.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk@xxxxxxxxxxxxx
> ---
> Rollei List
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