Re: paper and film testing

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sstoney@pdq.net
Date: 10/12/02-05:45:18 PM Z


Hi, thanks for writing back.

Yes, it is the view camera store service. I sent four kinds of
paper--Ilford, Azo, cyanotype on Crane's and cyanotype on Arches. Also,
they exposed five sheets of tri x for me and I developed it for different
times as per their instructions, in tubes, in D76 1:1. I got back a huge
package of printouts the other day, but I'm having trouble interpreting
them. There was one bundle that seemed to be just about the film itself.
There are five curves on this chart, and each one has an ISO and a
development time and an SBR. On this chart it says, "paper ES = 1.24."
This is about what Ilford is. So I assume that these curves apply if you
are shooting for Ilford paper. But, weirdly, the page of film curves for
Ilford paper is actually a little different. So I don't know what that
other page refers to.

For Azo, there is another family of curves geared to the azo paper's ES of
1.38. These curves are labelled with times in minutes and SBRs, but the
ISO is left blank for each curve. Same for the cyanotype print outs. So
I called Fred Newman and asked him what speed to shoot for the azo paper,
and he said that all the papers worked out to have about the same ISOs. I
guess that's why he didn't put the ISOs on the other curves. He says to
shoot for all papers at ISOs between about 250 and 320, for SBRs of 4.4 to
7.4, in the case of Azo paper. (To find out what the curves are for
higher SBRs, it seems I am going to have to do another film test at a
dilution of 1:2 for D76 instead of 1:1 as I did for this test.) Does this
sound right to you? I was sort of surprised that there was that much
uniformity for four different papers.

--shannon

> Shannon,
>
> I will be happy to try to answer any questions you have about the film
> tests. From what you write I understand that may have had film tested
> by the View Camera Store. If so, I am familiar with the method of
> testing since it is the one described by Phil Davis in Beyond the Zone
> System and it is a good system for calibrating film speed and contrast
> to your printing process.
>
> Sandy King
>
>
>
>
>>I have a question about paper and film testing that I'd like to discuss
>> with somebody knowledgeable about these matters, off the list, because
>> it involves the services of a business that does this. I had a paper
>> and film test done and I'm not sure how to interpret the results that I
>> got back. The company sent me five sheets of film that had been
>> exposed with a stouffer step tablet, and I processed them at different
>> times, and sent them back with paper samples that had also had a
>> stouffer step tablet printed on them. The idea was to figure out what
>> the right film speeds and development times were for different papers
>> and subject brightness ranges. I think Sandy was discussing his own
>> tests of this sort this past summer.
>>
>>--shannon
>
>
> --


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