Originally Posted by markbarendt
I try to referrence my statements and I have posted hard to find seminal papers. There are lots of knowledgeable people on this forum. Many of them are here because they love the medium and wish to give back. They are a great resource.
Starting out one doesn't have a clue where to start so one has to rely on information coming from others.
With all the passion I can muster, please know that your point has not been missed! Trust me on that one Stephen. Have a good day and I look forward to reading your articles.
Originally Posted by Stephen Benskin
I have two bulk loaders sitting on my desk awaiting speed tests before I use the film inside them... I expect APX-25 to be still good though expired '97 don't know about the 100
We do pretty well until someone says "it doesn't matter to me"
When what should have been said is "for my purposes, the difference is so small as to be inconsequential" (to paraphrase Todd-Zakia)
For every argument that "it doesn't matter" I am pleased to find an exceptional case where "it does matter"... and the key here for all us is to remain open. Think for yourself.. Does it matter to you?
Going back to the earlier reference to "minimum exposure to maximum black", not that I ever used this method anyway, I found Richard Henry's experiments regarding that methodology quite interesting. It may or may not work better with current VC papers in comparison to the graded papers Henry used for the tests, but there are still variables to be considered, and they are pretty much never discussed.
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Michael, thanks for jumping back in and for the Henry reference. Since Henry was evaluating the method as a way to determine a standard printing time and not as a way to confirm / determine film speed, he obviously didn't test the effectiveness for that purpose. He does have some interesting data on the the consistency of maximum black between paper grades. Notice how he mentions the effects of color temperature with both the response of the film and meter when describing the film testing part of the standard printing time test? He also graphs the effectiveness of the standard printing time method showing whether the the method is able to achieve its intended results. His scientific background is definitely apparent.
Originally Posted by Michael R 1974
As you wrote earlier, Henry wrote this book as a reaction to the misinformation he saw in popular photographic literature. Similarly, Mike Johnston once told me that Phil Davis never read any of the articles written by other authors in PHOTO Techniques because he couldn't stand all the bad information.
Last edited by Stephen Benskin; 01-19-2013 at 09:37 PM. Click to view previous post history.
I think I'll never comment on a film speed testing thread again. The whole "my nerdy testing method is better than yours" is completely inconsequential compared to how much a camera's shutter might work differently in bitter winter conditions or if a CLA is overdue.
There is a distinction between film speed and EI. Film speed involves precision testing to determine a numerical value that represents the sensitivity of the film. The other has more to do with how to personally apply the concept of film speed to exposure. Except for the ISO speed standard, all testing methods are concerned with finding an EI. Perhaps the whole point of my argument is that each has it's own purpose and not to confuse the two.
You just provided a great piece of info to the discussion, your knowledge is important here. It is important to consider that stuff.
Originally Posted by jp498
Part of the reason that I have basically "fallen back to" using manufacturer's recommendations as a baseline (box speed and normal dilutions, agitation, temperature, and times) is that I know they work and work really well. Similarly classic "point the dome at the camera" incident metering is so reliable that there is essentially no question about whether placement is workable or not.
Those two choices with a reasonable bit of practice to learn and to become even marginally skilled in the mechanics of these tasks ensures "pretty darn good" results that will fall well within a range of where a high quality print can be made from the resulting negative.
Which brings me to your point.
By good results I mean that I can say with confidence that, given my baseline, the resulting films will show faithfully my artistic choices and how well my tools are working. If there is a problem I know where to look, it is either my choices, my inattention, or my tools.
A solid tested baseline gives each of us the ability to trouble shoot easily and share that info with others.
It is important, if anyone is going to use my info as a baseline, to know how it works.
The reason box speed and classic incident metering works just fine for most people, including me, is that it pegs what is typically most important in a shot, like Grand ma and the new baby. The latitude inherent in negative films normally takes care of the edges nicely with room to spare. This systemically works so well that IMO the grand majority of all photographers could do this and never be disappointed with their negatives.
There are ways to tweak this though for the people who want that little bit extra to reach the next level of shadow detail in print or whatever is most important.
One of the reasons shooting at 1/2 box speed is basically irrelevant to me personally is my metering methods. When shadow detail is really important in the shot I simply orient the head of the incident meter to measure, for example, open shade, rather than pointing the meter head at the camera which might make it cross lit. A person using classic "point at the camera orientation" would need to use 1/2 or maybe even 1/4 box speed to get the same reading/exposure placement I get.
The inverse applies also. Where others may shoot at double or quadruple box speed in low light, I may simply orient the meter's head to peg exposure from the light source. Our exposure placement may actually end up the same but the logic used to get there is very different.
Without knowing the mechanics of the system I employ knowing my EI is irrelevant.
Not knowing how your shutter behaves in the cold provides the same problem.
Last edited by markbarendt; 01-20-2013 at 09:06 AM. Click to view previous post history.
Mark Barendt, Beaverton, OR
"We do not see things the way they are. We see things the way we are." Anaïs Nin
The reason I started down this speed testing path, is I wasn't getting the results I wanted on paper. And that was by shooting at box speed and developing according to the manufacture's directions. I really didn't want to test, but by testing, I'd hoped to arrive at a standardized set of actions, from exposure to print. By standardizing my workflow, my hope was that I could find out where I was going wrong. It could be that shooting at box speed isn't my issue. It could be my metering technique, my developing time, my enlarger, my camera's shutter, etc.
Like many people starting out, I'm clueless. I'm not in a position to critically evaluate testing methods, which there doesn't seem to be a shortage of. Some methods use a densitometer, some don't. There's the test for zone I or zone III debate. People recommend changing the shutter only, changing the aperture only, changing ISO only, during the test. Shoot a gray card, shoot a wall, shoot a real scene, shoot a set of props, etc. Test at one stop, 1/2 stop or 1/3rd stop gradations. And so on.......
One of the positive consequences of all this variety, is that it's forced me to continue studying and I'm starting to slowly understand some of this stuff.
In the end, I think we all come up with our own methodology for testing, conscious or not. Repetition, practice, testing, whatever you want to call it, it leads to the same end, our personal understanding.
Everyone who has contributed to this thread has helped me. I'm not just saying that. I've discovered I already have a consistent workflow based on factory recommendations, with the exception of printing. A speed test isn't probably where I need to start. I think the most valuable thing for me at this time would be to find my "maximum black" print time, so I have a baseline in which to evaluate, how my negatives print. I just came to that realization today.
Now having said that, I shot my first rolls of speed test shots yesterday, so I'm going forward with testing anyway. I'm sure I'll learn something along the way.
I'll close with a couple reads I found interesting:
On this website http://www.barrythornton.com/ go to "technique guide" and choose "The NoZone System." This seems like a good way for ongoing evaluation and tweaking. If someone sees any glaring holes in this article, please let me know.
And this article, http://www.davidkachel.com/historical/calibrat.htm made me aware of variables I hadn't even considered effecting results.
Thanks everyone for your help!