From: Tom Ferguson (tomf2468@pipeline.com)
Date: 04/10/03-12:00:13 AM Z
They are fine from here. This page is on my ISP "free space" and I must
admit it is sometimes unreliable. Try again!
On Wednesday, April 9, 2003, at 02:09 AM, Stane Kočar wrote:
> Tom, I tried to look on your web site, but the pictures are missing (in
> my
> Microsoft Internet Explorer).
> What about others?
>
> Stane Kocar, Slovenia
>
>
> ----- Original Message -----
> From: Tom Ferguson <tomf2468@pipeline.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Wednesday, April 09, 2003 2:33 AM
> Subject: Re: Film Speed and Negative Development
>
>
>> Scott, something is odd! In "general" using the 0.1 over FB+F (fine for
>> silver gelatin, not so good for many/most alt processes) you will get
>> "about 1/2" the company rated value (FP4 rated at 125, personal EI 64
>> or
>> 80). Different developers don't change it that much :-(
>>
>> For you to be getting "3 to 4" stops lower (EI 16 to 8) indicated bad
>> developer,bad testing technique, bad meter, or bad film.
>>
>> For alternative process work a good "general" rule is to decrease your
>> "silver/0.1/Adams" EI test by 2/3 stops. If your FP4 manufacturer is
>> ISO
>> 125, "silver/0.1/Adams" test is EI 64, use EI 40 for alt. That is very
>> "general". I have an article you can read about film testing for alt
>> processes at:
>> http://www.pipeline.com/~tomf2468/altinstruct09.html
>>
>> But again, for you to be getting " 3 to 4 stops" (as opposed to my
>> "estimated" 1-2/3 stops) is odd enough that I "assume" something is
>> "broken or bad".
>>
>>
>> On Tuesday, April 8, 2003, at 04:36 PM, Scott Wainer wrote:
>>
>>> Greg,
>>>
>>> I can almost live with whatever film speed I get. I thought that it
>>> might be
>>> about 1/2 - 1 stop less, I just didn't expect it to be 3-4 stops less
>>> than
>>> what the manufacturer rated it at. If that is truly the case then I
>>> will
>>> just go back to shooting Pan F+ (ASA/ISO 50) which gives me an EI of
>>> 32
>>> with
>>> the same setup, chemistry, and processing.
>>>
>>> What I don't get is that all of the published data shows a higher EI
>>> than
>>> what I am getting; some times higher than what the manufacturer rated
>>> it at.
>>> Could my setup be that far off that I am loosing 3-4 stops?
>>>
>>> Scott
>>> smwbmp@starpower.net
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Greg Schmitz" <gws1@columbia.edu>
>>> To: <alt-photo-process-l@skyway.usask.ca>
>>> Sent: Tuesday, April 08, 2003 7:13 PM
>>> Subject: Re: Film Speed and Negative Development
>>>
>>>
>>>>
>>>> Scott:
>>>>
>>>> I don't want to rain on your parade, but it has been my experience
>>>> that it is almost impossible to raise the true speed of any film - no
>>>> matter what. I have exposed and developed hundreds, perhaps
>>>> thousands
>>>> of rolls of test film. In reality what is usually meant by an
>>>> "increase in speed" is really an increase in contrast. The point at
>>>> which the films curve begins to pivot upward does not change, it just
>>>> gets steeper. I have seen minimal increases in true film speed
>>>> with a
>>>> few special additives, pre/post-exposure, and exposing film to
>>>> certain
>>>> gas fumes.
>>>>
>>>> Depending on what your criteria are for your negative you may well
>>>> find that your final results are lower than that stated by the
>>>> manufacturer. I base my film tests directly on the requirements I
>>>> have for a given type of positive and frequently rate the films'
>>>> speed
>>>> differently for the process that I am using to produce the final
>>>> positive. My standard exposure for Tri-X 135, for example, is
>>>> usually
>>>> either 200 or 320.
>>>>
>>>> -greg schmitz <gws1@columbia.edu>
>>>
>>>
>>>
--------------
Tom Ferguson
http://www.ferguson-photo-design.com
>>
>
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