Wow, thanks. I had missed that all these years because the same thing was printed with my last (really last) HT-2 kit from years ago. Yes, it is nearly one of the last pages in my 1969 Dataguide along with the instructions and all of the information. And here I had missed it all these years. I had been reading the development times and methods but not that last section.
I just read over it a couple days ago, and I don't think it is as comprehensive as the actual datasheet from the Hypo Estimator, but I could be wrong.
I have no comparison now that the "stuffer" is gone missing, so IDK. Can't help.
Density of Stain vs. Estimated Grams of Thiosulfate Ion/sq. meter
Originally Posted by Photo Engineer
Well this is a yardstick that don't measure up to the job!
I'll explain that in simple terms.
A 35mm film is about 0,06 m2
Fixer is about 20% solution
In the film remains about 12 ml fixer absorbed in the emulsion, that is about 15 gram of solutiion.
Weight of fixer 15g x 0.20 equal to 3 gram fixer in the film.
Filling the tank from emty dilutes everything 1:20 and after a very short time equilibrium between concentration in film and water is reached (this time gets slightly longer as the concentration sinks)
Concentration before washing 3gram / 0.06 m2 = 50 gram per m2
1. tank 50 g/m2 : 20 = 2.5 g/m2
2. tank 2,5 g/m2 : 20 = 0.125 g/m2
3. tank 0.125 g/m2 : 20 = 0.00625 g/m2
Look at these numbers once again:
The test goes down to 0.01 g/m2. If that is archival quality, fine by me.
But the number show that 3 tanks after the Ilford method is already at a theoretical limit of 0.006 g/m2 in my book that is already past what you can HOPE to measure, by your indicated measuring method.
Now, I was under the impression that the Ilford method was not up to archival standards, I was assuming that we need to reach at least 0.001 or lower (from memory). That will be reached by more changes of water, easily and effortlessly.
But you cannot measure THAT by this method, you don't have maesuring RESOLUTION down to that level with this method.
Is that concept so damn hard to grasp?
Don't get so excited.
See what others have posted.
We do not have fine enough tools available to us to test part of what you are describing. But, all we need are 3 points. ANSI Archival, Commercial and BAD. We get a "very bad" point as well. So, with the points we have being approximate, anything visually equal or better to Archival (or Commercial if that is your aim) is OK. Otherwise we need very exacting lab tests.
And, since it does not matter how we got there, your flow rates are not useful either. Especially since the local water supply can often introduce HUGE variations into the results. Greg has given us what works for him and a template to work from. It is an excellent test. As I said, I believe the actual lab results just as I believe the ones I did with paper. I would not believe any calculations on paper whatsoever.
My truism in photography is "Do what works for you!".
And, BTW, I used to get analyses of retained Silver using X-Ray Fluorescence and I got it as a function of fix time and wash time so that I could obtain data such as you calculate so that I could prove that fixation was complete in X minutes. But, I never relied on calculations, let alone stand-alone calculations!
Well, no. Theory gets tested and verified (or refuted) by repeatable experiment. The only way one knows a theory "works" is by checking a predicted outcome against actual outcomes.
Originally Posted by Erik Prestmo
Knowledge is based upon evidence and observation. Theory systematizes or abstracts underlying relationships. Theory attempts to formulate a simple statement of cause or of relationships in the facts. Such as "energy will equal mass times blah blah blah". First we propose a theory, then verify by experiment and observation.
In this case, we wash then test the outcome. If the factual results are unexpected, we revise the theory. So I would reverse your statement and say, "knowledge is what theory is based upon".
Here is the documentation that came with the Kodak Hypo Estimator Pub. No. J-11.
Well Greg & PE read the fine print! where does thosae two documents state that this test is adequate for determining if film or paper tests out "for archival purposes"??
If you read ALL and the disclaimer, it clearly states that this test or test procedure "does not meet ANSI standadrd etctecetc" and that to determine if one reaches archival standards one need to trust other testing methods, described in said ANSI standards......
While the simple calculations suggested by me indicate what to look for.
This discussion is nothing but Seven Angels dancin on a pin head.
Go find something else to do!
I see these Dataguides frequently on Craig'slist ads for "complete darkroom" where it is included with a little 35mm enlarger, expired Polycontrast paper, Voss lens, and three 5x7 trays :)
The info on the test is not as detailed as Pub J-11, but thanks to Greg we now all have J-11!
First, I never made any claims. I stated I was going to test the published washing methods and test it against a Hypo Eliminator using HT-2 solution and post the results. That is what I did, and I have refrained from making any conclusions from the tests. The results of the test are what they are.
Second, if you want me to produce more conclusive tests that meet your needs, then give me the mass spectrometer or whatever tools are needed and the training to use them. I am an artist, not a chemist. This test is designed to give me a visual approximation so that my non-chemist training can have something to work from. But as I said at the beginning, if you want more conclusive evidence, then do the tests yourself and get back to us with the results. The whole reason I did this is because people were arguing, as you are, without actually doing the tests and seeing the results. If you disagree with the data here, then prove it wrong with results.