The first of those I cite comes from the work of J. L. Tupper and was published in the '40s IIRC. Both Mees and Haist published variations on the second two from their work in the '40s and '50s. The work published by Mees was also originally done by Tupper and others on Mees staff.
PE
During our surveys, the "customer" selected that as the "First Excellent" print. Yes. But the consistently better prints started at point "Z"
During our surveys, the "customer" selected that as the "First Excellent" print. Yes. But the consistently better prints started at point "Z" and consisted of the straight line portion of the curve.
Acceptable print quality improves up the scale and then goes down again Stephen. Max is in the middle which is above "Z".
Have you ever run a test yourself with literally hundreds of prints? Maybe more?
PE
If I'm reading the graph correctly, Point Z is the highlight density of the "Just Acceptable" print. I'd love to see a specific example that defines this as the optimum point for shadow placement to substantiate the claim.
Now, it is clearly impossible to do all of this
PE observed and for this extremely strange curve, Z also indicates the beginning of the straight line. For this crazy film, PE says that's the most excellent shadow placement. And based on the crazy graph, I think he's right. But this is a crazy graph where that point is more than 3 stops above the minimum exposure. It's just a bad example.
We should really get a better graph to discuss the beginning of the straight line because usually I find the best exposure to be.. not 3 stops overexposure... more like 2/3 stop overexposure.
If I may interject with a question about Tri-X 320 and it's curve shape, I have never understood why it was designed that way.
Kodak says its curve (long toe, upswept thereafter) is well suited for tone reproduction under controlled lighting situations.
We also know when flare is present, the toe of a film is flattened, meaning under "uncontrolled" situations the low ends of the curves of shorter toe films (most current films) will tend directionally toward that of Tri-X 320. Most of us would call this effect undesirable. However since subject flare is beyond our control in the field there is nothing we can do about it other than perhaps give more exposure.
Yet Kodak designed this apparently undesirable toe shape into a film intended primarily for use under controlled and/or low flare conditions - precisely the conditions under which we might not otherwise have to settle for a flare-induced long toe. We could use Tri-X 400 under those controlled conditions, and retain its shorter toe and long straight line, but instead Kodak gives us a film that, under controlled conditions, "mimics" the effect flare has on the low end of the curve of a short toe film under uncontrolled conditions. In fact, depending on which developer is used, Tri-X 320 can be "all toe".
Does this not imply in Kodak's view, from a tone reproduction perspective the native toe of Tri-X 320 (or the flare-affected toe of a straight line film) is desirable? The emphasis in an unmanipulated print would be on strong mid-tone gradation relative to shadows (which seems to be what observers focused on in identifying first excellent prints).
If you look at figure 20.5 in Mees, in the example supplied, you see that after the first acceptable print (point "A"), you will note that the caption then reads "Higher quality than first acceptable print". This is exactly the point that I have been trying to make. You get an acceptable print followed by even better and better prints until quality begins to decline as you run into the shoulder. It does NOT mean that the first acceptable print is the best that can be done. It is the print that is selected from a bundle of prints from over and under exposed negatives that "customers" call the first one they would accept!
PE is correct 'firstacceptzable'does not mean best but they were close.
So in the first excellent print how far away was the not quite the first excellent print and the better by a bit than the first excellent print from that chosen? The corollary of course being if either of those had been chosen instead how much practical and theoretical, on speed, difference would ensue? Is it implied by PE giving a, and the term safety margin is contentious I know, an extra one third of stop that we are that close? If so I commend the process and am not surprised a large statistical sample was required to obtain a valid result.
Ron, this has been what I've been talking about for years. No one has proposed First Excellent Print produces the highest quality prints. If you are referring to the caption in Fig 20.5 "Higher quality than first excellent print," I did notice that. I wrote it.
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