Re: Bergger Versus Forte/ PMK testing.

Thanks Sandy;

I can agree with the Classic versus the Forte 200
as I am positive beyond doubt those are the same
beast (knowing the histories and who sells them).

The Bergger versus Forte based on what I am
seeing merits some additional testing perhaps using various developers.
I will heed and consider what your say, as I value your input.

I am again saying at this point; that I was extimating 20% so it could
be more. The Bergger rated at 200 is clearly better.
The Forte lacks density as has been my experience,
I intially anticipated no difference so the results come
as some surprise.

My secondary question based on your statement, is this;
if they are the same film (Forte & Bergger) would not the stain
in the base non image areas match, they do not,
Bergger again has alot more stain.

on 5/3/04 1:43 AM, Sandy King at sanking@clemson.edu wrote:

> I have also tested the three films produced at the plant in Hungary
> (Bergger BPF 200, JandC Classic 200, and Fortepan 200) and in my
> opinion they are one and the same. A 20% difference in density is not
> all that significant since you will easily find that much difference
> in films we know for sure to be the same. And of course the more
> density you have, the more stain there will be.
>
> The curve of a film tells you more and the curves of these films are
> virtually identical except for some minor differences in emulsion
> speed, which I attribute to conditions of storage, age, emulsion
> batch, etc. But when you adjust the curves for density you find that
> they are mirror images of one another, and all of the films have
> virtually identical N expansion and contraction potential.
>
> As far as I am concerned these films are the same duck since they
> look and quack alike, even though one may quack a bit louder from
> time to time.
>
> Sandy King
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>> I can not remember whether it was in this forum that
>> the question of whether these 200 speed films are the
>> same was ask. Never the less I have done a side by side
>> comparision, by my intial test it appears they are not.
>>
>> I shot both 120 rolls under identical conditions, controlled
>> ambient daylight, metering from a centrally positioned
>> grey card. Both films were processed using the Bergger suggested
>> PMK time of 12 minutes, I processed both rolls in the same tank
>> using 500ml of solution, dilution was 1+2+100 at 68F. I did add a pinch of
>> amidol to increase the overall speed for both films.
>>
>> The end result, appears that Bergger produced both a denser
>> and more highly stained roll of negatives. The difference is what I estimate
>> to be approximately 20 %....for both stain and density.
>>
>> Perhaps as was stated by someone else the film is made at the same plant
>> using Bergger's specification. The paper backing is the same, the film base
>> appears the same,spools and paper tape the same.
>>
>> Anythoughts?
>
Received on Mon May 3 06:05:15 2004