I attach my sketch of results from "Controls in Black and White Photography" by R.Henry p240, for Tri-X Pan film in Beutler developer, indicating how density of a print from film exposed under a knife edge varies with distance.The slope of the line indicated gives a numerical value for the acutance.The adjacency effect is shown as a drop in density that extends over some distance from the knife edge.
Dr Henry says:
"Since it is admitted that the sense of sharpness depends not only on acutance but also on adjacency effects,either the formula for acutance should be changed somehow or other to include the edge effects or or a new term should be introduced to include both"
I don't think this was ever done, and it is unlikely that Altman and Henn could have solved this problem.
Modern tabular grain grain films have a very high acutance as defined by the slope of the line but little adjacency effect.
Old type films had lower acutance as so defined but showed more adjacency effect.
Here is an example from Kriss et. al. I have posted this elsewhere with more description.
Hi Michael, a couple of corrections to your pdf...
There were actually three films tested, you didn't mention the Plus-X Pan. And their gamma aim was actually 0.65, not "~0.63), as I quoted in post#9.
And a general note to all readers: I call the developing agent "Elon," per the original paper, which also says "*Kodak's Elon Developing Agent is the Eastman Kodak Company trade name for p-methylaminophenol sulfate." But apparently Metol is the generic trade name for the same thing.
Here's your question list and some answers (I didn't proof-read carefully, so may be errors; if anything looks funny, please ask):
Some methodology questions:
Q1. Were pH figures presented in the original paper?
A. No. Here's a more complete excerpt from Altman and Henn:
*Rather than type the full text of the high-sharpness section, here is a pertinent bit (re: AH-15 through 18):
Developer Formulas. The first step in the experiment was to formulate the appropriate series of developers. This was done by the sensitometric testing of preliminary formulas with the aim of establishing reasonably uniform activity levels and development times. The first section of Table I shows the composition of the fine-grain series (Series I).
The central formula in this series, AH-3, is essentially Kodak Developer D-25. It is a true fine-grain developer, giving grain reduction at the expense of reduced emulsion speed. The solvent actin has been lowered in the AH-1 and AH-2 formulas by decreasing the sulfite content. Since this reduction would lower the pH and the activity as well, most of the bisulfite was removed in AH-2 and Kodak Balanced Alkali was added in AH-1. Formula AH-4 contains more than the usual amount of bisulfite. This maintenance of approximately constant activity was considered essential since Henn and Crabtree (J. Photo. Soc. Am.,1: 727 (1944)) have shown that graininess is affected by both activity and sulfite contents.
The solvent action is obtained from the combined effect of the sulfite and bisulfite, and these are totaled as moles of sulfite ion in the table.
Q2. Why was a buffering alkali used – particularly for the sharpness developers?
They all contain 10 grams of sodium sulfite per liter and the proper amount of alkali to equalise the activity. Full compensation of activity was not possible in the case of AH-18, containing the least amount of Elon, but the others are matched reasonably well.
A. I don't know, other than what is in the quotes above.
Q3. Was agitation consistent for all tests?
A. All that is said is:
Q4. Was D-76 used at stock or 1+1 strength in the Tri-X test?
Processing was in the sensitometric machine of Jones, Russell, and Beacham (Jour. SMPE, 28:73 (1937) which gives strong and uniform agitation.
A. The table for Tri-X simply lists "Kodak Developer D-76 (footnoted "average of 2 runs"). So one has to consider it to be straight D-76. I don't know why they would change dilutions on this one (the other two films were both noted as "1:1"), but the actual development time they used is consistent with 1970's era development times in straight D76. So I would consider it to be straight D-76.
Q5. Why would the developing time for AH-15 be longer shorter than for AH-1 if the only difference between the two developers is a lower Metol concentration?
A. I don't have a sensible answer. It's worth noting, though, that they attempted to develop to the same gamma - their developing times originated from prior time-gamma studies. I'll look the data over a bit more.
Thank you for the feedback and I appreciate the corrections as well. I "assumed" they had targetted a gamma of ~0.63 or 0.62 simply based on the results data, as in Haist there was no specific mention of the actual target. Regarding the third film, I was not aware they had also tested Plus-X. Unfortunately only the Pan-X and Tri-X experiments are mentioned in Haist.
At one point I also thought there might have even been more developers too, filling in the numerical gap between AH-4 and AH-15.
I'm attaching the corrected PDF for reference.
I am still fairly puzzled by some of the results, which is why it would be interesting to redo this experiment with current films. For example, based on the Altman and Henn Tri-X results, I'd probably have to conclude D-76 was a virtually ideal match to that particular incarnation of Tri-X and must have worked exceedingly well with it, giving the best possible results for each of the variables in the triad. At least when it comes to the AH Metol-sulfite developers and variations, D-76 could not even be bested in any one characteristic, let alone two or three.
We might also conclude that although every film had to pass certain tests in D-76 to be released by Kodak, D-76 may not have been a great match for Panatomic-X. I am basing this on the D-25 (AH-3) results, where a developer known to be of the "extra-fine grain" type, produced the expected granularity reduction, but a relatively small speed loss, and no loss of acutance compared with D-76 1+1.
Last edited by Michael R 1974; 12-20-2012 at 10:31 AM. Click to view previous post history.
With respect to the developing times in AH-1 vs AH-15:
As Michael points out, the only difference between them is in the Elon content:
AH-1 has: 7.50 g/l Elon, 10 g/l Na2SO3, 4 g/l Kodalk
AH-15 has: 2.50 g/l Elon, 10 g/l Na2SO3, 4 g/l Kodalk
So AH-1 seems as though it would be the more "powerful" developer. Yet in all cases (all 3 films) a longer development time was needed to hit the aim gamma.
An odd side effect is that the longer development (in AH-1) gave significantly higher film speeds (despite the similar gamma results). This might happen if, for example, AH-1 initially built low densities at a faster rate than the high densities. Then, after some extended time, the higher densities finally began to climb.
It's possible, too, that some odd sensi curve shapes were involved also. Determining gamma is not an exact process with a wobbly curve. Also, the speed point is not a fixed density in this test, they refer to the 0.3 G-bar method per standards at that time.
I'll type in another paragraph with their test criteria.
Last edited by Mr Bill; 12-20-2012 at 10:30 AM. Click to view previous post history.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Here are some details of evaluation (from the Altman-Henn paper):
*note, for symbols I can't make, I'll give my version in "", as well as stuff in the citations using "()":
(After processing in the sensitometric machine of Jones, et al)
I know this is not too helpful, but at least no one needs to wonder if the original paper gave useful methods.
The resultant strips were evaluated in accordance with standard practices described in the literature. The speeds which will be cited later in the paper are 0.3 [G bar] speeds measured according to the familiar ASA criterion. Granularity was measured in terms of the root-mean-square of the granularity fluctuations (G.C.Higgins and K.F.Stultz, J.Opt.Soc.Am.,49: 925 (1959)). The diameter of the scanning aperture was 24 [microns] and the sample density was unity. Acutance was measured as described by Perrin, (Jour.SMPTE,69:151 (1960)) the sample density was also unity. Since the curve shapes were similar, a single number at a constant density is a reasonable indication of the behaviour of the developers.
There is a little more to go on, for anyone who has the first version (Thomas Woodlief) of the SPSE Handbook of Photographic Science and Engineering. In the Chapter "Image Structure and Evaluation," a section on "Graininess and Granularity" is written by Altman. Also, a section on "Acutance and Sharpness" is written by Perrin. Since the book is published in 1973, one might wonder if these things have changed since the Altman-Henn paper we are discussing. It seems not, since the SPSE book includes pertinent references which are the same as above, or older. (note that the Altman-Henn paper was originally presented in 1959, but was published in 1961)
I have two comments on these excellent observations.
The questions you ask would all be similar to those asked by others reading the internal AH report. Don't you agree? Well, my hypothesis is this. Those questions were answered in the original and unedited report, but were deleted either for brevity or due to the fact that the information was deemed classified at that time. I prefer the latter. Reports at EK sometimes ran to a hundred pages, and were required to be complete. They were vetted before internal publication.
My other observation is the fact that Metol (Elon) is very acidic. Therefore, the pH drops as Elon concentration goes up. Readjustment of the pH is essential, but it does change buffer capacity. So, in the high Elon developers either the pH was low and left that way for some reason, or it was adjusted and that may have changed the developer. Again though we may not have all of the information.
I caution you not to overanalyze. I am sure that Grant meant this as a guideline and not a reference.
PE are you referring to the observations in my PDF and in the thread, or the observations/clarifications Mr. Bill is quoting from the study? Sorry I'm just trying to make sure I don't get too confused here....
But I agree it seems like overanalyzing - particularly with the redacted summary version in Haist, is problematic.
I wish I had access to a microdensitometer or someone who could to RMS granularity and acutance measurements on tests. I could then carry out a similar study with current films. I have lots of ideas.
Hey maybe I could do all the developer/development/contrast work and then send it to Chris (Holmburgers) at GEH to do all the granularity and acutance testing HAHAHA
Well Michael, I was really referring to all of the comments. They are right on, but unanswerable for the most part due to the redacted text we are presented with. I may have actually read the report or read Grant's original of that text, but it was about 1970 or so.
I doubt that there is any equipment at GEH to do the work you are considering. If I find any I'll let you know. Holmburgers is on his way home today to be with family over the holidays. I can ask him when he gets back.
I have heard that there may be some equipment around Rochester somewhere. I've never bothered to contact anyone to follow up. After all, it is a labor intensive job doing the readings and then the plots from the raw data.
Just kidding about Holmburgers He's got better things to work on there than my silly stuff. And it ocurs to me I wouldn't know know how to properly use a microdensitometer even if I had access to one.
Just one correction of a typo in one of my "questions" (which Mr. Bill has already tried to answer) in case it caused any confusion:
"Why would the developing time for AH-15 be longer shorter than for AH-1 if the only difference between the two developers is a lower Metol concentration?"
Obviously it should have read "Why would the developing time for AH-15 be shorter than for AH-1..."