Thanks Chuck, this fits in perfectly with the critical thinking concept of the thread. And please understand that while I'm using your post to help illustrate my point, the choice is mostly happenstance. We are all guilty of doing the following.
Definition:
Logical Fallacy: In logic and rhetoric, a fallacy is incorrect reasoning in argumentation resulting in a misconception.
You can see the curve reaches a 0.1 negative density at Zone I, not at Zone I 2/3 or Zone II. Flare? Perhaps it is incorporated into the speed point, IDK, but I know what you think
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In the type of testing you are showing in your examples, it is. Its only the testing procedures that are flare free, not the interpretation of the data. You contacted the step tablet; therefore, there is no flare. The film curve plotted shows how the film responds to exposure and development. It is without flare. The reason speed point falls only 3 1/3 stops below the metered exposure (fact) when the shadows falls 4 1/3 stops below (fact) is because flare brings the exposure back up to the speed point (fact). So, what you are doing is incorporating flare into the speed analysis of a non flare test.
Traditional Zone System is different. While it uses an optical system, the resulting flare is minimal. It has the speed point 4 stops down from the metered which is a 2/3 stop difference between the two methods. You have misstated the argument (Logical Fallacy).
You are also begging the question in which the proposition to be proven is assumed implicitly or explicitly in the premise. I guess you could also consider it circular reasoning. You can see the curve reaches a 0.1 negative density at Zone I. Isnt the definition of Zone I the point on the curve where the density is 0.10? The fact that the curve encounters Zone I at some point only proves that the film encounters Zone I at some point. You are saying its correct because you got an answer without proving proof. What is required is the exposure value at that point.
Since it is a speed test, Kodak's ISO speed of 100 was used. I'm getting full box speed with TMX and D-76 1:1.
More circular reasoning, which can be eliminated by explaining how you know you are getting full box speed from the test. The question with Schaefers method is whether the exposure you think you are getting is what you are in fact getting. Film speed is based on how much light is required to create a certain density. Youre missing that very component in the equation. But as this is a separate issue from the topic about the relationship of flare and the determination of speed between to testing methods, it is simply mudding the waters (another logical fallacy).
If your testing methods are consistent, you can accurately compare the results of one test against another using only relative film speeds, but the actual value of the film speed remains unknown. This is what youve done with the two examples youve presented. If the exposure part of the testing method has remained consistent, any difference in the results have to be attributed to the component of the method that has been changed. In our case, the developer. Therefore, your examples are a fine demonstration of the affects of two different developers on film speed. However, this is an argument from a false premise or specious reason. You are presenting an argument that mistakenly attempts to establish a causal relationship where one doesn't exist. Your results can be attributed to changes in development and not exposure because in your test the exposure was the same and the development was the variant. However, you are falsely presenting the premise that these same results can address the question of the accuracy of two different exposure methods. You cant prove or disprove something if you havent first established a causal relationship. (Ad hoc fallacy? also known as the false cause fallacy). I could also add data mining in that youve selectively chosen an example in an attempt to prove your point simply because there is a 2/3 stop difference in their film speeds.
AA contends that flare is accounted for, IDK, really. Am I drinking the cool-aid, I'm sure many will say yes. Perhaps the flare is just not as much of factor in my system as some may think it should be, IDK.
Argument from authority. Just because someone in authority says something doesnt mean its correct. An argument requires proof. I have shown how flare works in camera and how in testing procedures it is at a minimum. And contacting eliminates any flare from testing, so it has to be incorporated into the analysis. Flare isnt a factor in your testing system, but it is a factor when shooting.
This is the method taught by Schaefer and one that is under the gun here in that it is not believed that it represents "reality". I contend that the "reality" is simply not that great of a difference.
That should be the norm in any testing method. Does the testing reflect the results obtained by use and are the tests accurate? The ISO film speed standard brought some some major changes to it in 1993. The ISO developer changed as did the method of development and the hold time because they felt the changes would result in testing that more accurately represents reality (also know as the type of results you get in use).
Chuck, you tend to interpret my analysis of some point of theory from the standpoint of a false dichotomy which only presents two choices. It is either all one way or the other. Well, it can be many different ways. A system can work and still have inaccuracies, and just because it works doesnt mean it is entirely correct. Your contention as to whether reality is simply not that great of a difference is an argument from incredulity. Facts dont depend on whether someone can accept them or not (ie I dont believe in Evolution. Or I believe the Earth is 6000 years old or I cant accept that
.).
Other than the Pragmatic argument this is most often use by you. You haven't addressed directly any of the examples and models I've presented (including a curve from Adams' own book). How was the reasoning wrong on that one? It's only wrong because you can't accept it. We're living in a country accepting where incredulity is increasingly trumping scientific consensus. Can we please stop it's spread here?
You can get results from your testing that work for you (pragmatic fallacy), but that doesnt address the question whether a point of theory is correct or not. And simply because you see an absence of something doesnt mean it is absent (another logical fallacy). With point of theory here, there is, you just dont know its there. Your making the assumption that the interpretation of the data from your non-flare testing method applies directly to usage without ever confirming the results or fully thinking things through. Your testing method excludes flare, flare exists in shooting conditions. These facts need to be reconciled not denied.
Logical fallacies are the enemy of critical thinking. If critical thinking came easily for us, we wouldn't have had religion for 100.000 years before we had science.
I began this thread to propose a thought. Are we properly questioning the various aspects on how the photographic process works? To help illustrate that question I use a few points of theory as examples.
If attached the proof of my concerns about the accuracy of Schaefers film speed testing method.