[pure-silver] Re: Are most photographers visual learners... a little OT
- From: Laurence Cuffe <cuffe@xxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sat, 10 Nov 2007 21:25:20 -0800
On Saturday, November 10, 2007, at 03:37PM, "Dave V" <DValvo@xxxxxxxxxxxxxxxx>
wrote:
>Sorry to mislead. I will disclose answer later, was wondering if others
>knew.
>
>----- Original Message -----
>From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
>To: <pure-silver@xxxxxxxxxxxxx>
>Sent: Saturday, November 10, 2007 3:28 PM
>Subject: [pure-silver] Re: Are most photographers visual learners... a
>little OT
>
>
A nice question.
Previous to 1900 I don't believe that the quality of plates was well
controlled. My evidence for this is circumstantial and is based on the
widespread prevalence of development by inspection, which allows one to
compensate for limited errors in exposure. In addition to this the use of
various reducing formulae to control the contrast characteristics of the
negative also seems to have been widespread.
In the 1870's Swann developed the dry plate process which was a trade secret
until revealed by Bennet. Mr Eastmann read Bennets paper in the BJP and
traveled to London where he was unimpressed by the state of the art English
facility for coating plates, where it was all done by hand.
Eastmann returned to the states where he developed a two layer process where
the silver containing emulsion is coated onto a paper backing which was
pre-coated with gelatin. The resultant combined coating could be striped from
the paper backing and coated onto standard glass plates.
The next substantial development was flexible transparent backing for the
emulsion, presumably cellulose nitrate bu I dot know how this was coated.
How am I doing Prof Valvo?
All the best
Laurence Cuffe
>>
>> ----- Original Message -----
>> From: "Dave V" <DValvo@xxxxxxxxxxxxxxxx>
>> To: <pure-silver@xxxxxxxxxxxxx>
>> Sent: Saturday, November 10, 2007 9:19 AM
>> Subject: [pure-silver] Re: Are most photographers visual learners... a
>> little OT
>>
>>
>> Becky, I'm sure I'm not typical of those that read this post. I have more
>> science background than photographic (trying to fix that in retirement).
>> I have a masters degree in Image Science from RIT and spent 36 years at EK
>> from building photographic test systems to introducing new B&W papers. I
>> have taught the science side of photography to thousands of people (most
>> at Kodak) but also in 5 countries. You can't imagine how trilled I am in
>> retirement to finally shoot images for myself rather than test targets or
>> Shirley's. (Whoops! I just let a Kodak tidbit secret out of the bag.
>> The first Kodak female model's name was Shirley. Every time someone
>> needed model images, Shirley was called. And we called the process
>> ....get some "Shirley's" on this new film or paper. When a new model came
>> along, with a different face, she was still called Shirley. After almost
>> a hundred years of shooting tests and models there have been a lot of
>> Shirley's. ) You won't believe how boring it is to look at Shirley's.
>>
>> The things Shannon is doing is using an instrument to measure density and
>> a pencil to plot the results. A great learning experience and a lot more
>> precise than "looking " at an image.. Some people have listed the books
>> printed that describe the process. That said. Before Kodak introduced
>> sensitometry and densitometry does anyone know how the manufacturing
>> coating process was tested and controlled????
>>
>> ---------------------------------------
>> Do you know when Kodak began to use sensitometric testing? The basis of
>> the science is due to Hurter and Driffield. The citation is to their
>> paper:
>>
>> Ferdnand Hurter and Vero Driffield, "Photochemical Investigations and a
>> New Method of Determination of the Sensitiveness of Photographic Plates",
>> The Journal of the Society of Chemical Industry, May 31, 1890
>>
>> Certainly Mees must have been cognizant of this but I wonder if GE or
>> anyone else at EKC was. Mees joined Kodak in 1912 but the principles of
>> H&D must have been known there earlier.
>> ---
>> Richard Knoppow
>> Los Angeles, CA, USA
>> dickburk@xxxxxxxxxxxxx
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>
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