William Robb wrote:
----- Original Message ----- From: "Otis Wright"
Subject: Re: The Wilhelm testing method. Was Re: OT:
Photographic Materials
Can see you not into materials testing. Guess we canforgo testing
contstruction in the future.
And this has what to do with testing longevity of photographic materials? But really, do you test construction materials by seeing how it reacts to 100G?
Why not? Are you saying there is not material/application where tests at that level are meaningful?
[I do get your drift, so I'm not trying to run this one out too far.]
I'm always in left field. Having worked in and around material testing since '58 and being a current regular purchaser of material testing services, references to Wilhelm's work here some time ago caught my eye and I picked up a copy of his "The Permance and Care ......." My limited tech work in Photos didn't flag the work, and it seemed like a reasonable approach, subject to someone providing a studied objection, and someof the 50 plus year old photo products around here seemed to suggest he was onto something --- but the sample is too small to mean anything. In any case, I understand where your coming from, but I don't think I'll through the book out today.
Opinions from left field are interesting but not veryconstructive. Of
course if you have material performance data thatrefutes Wilhelms
work, it would be of some interest.
Well, I do have some RC prints that have lasted far longer than Wilhelm says they would, based on his testing procedures. No yellowing, and no delamintating. The problem with his method is that it depends on extrapolating results from a presumption.
This is not coming from left field, this is coming from someone who has, like Wilhelm, spent most of his life working in the technical end of photography.
William Robb
