Based on experience I would advise caution. The Zone System can become a rabbit hole...
Based on experience I would advise caution. The Zone System can become a rabbit hole...
as I purchased a densitometer (for alt process) thought I'd see how close my zone 1 is to AA's recommendations.
For 35mm format film, Nikon ES-2 digitizing adapter is very convenient for these purposes.
Mark,MattKing. First of all, using a towel could be problematic unless the towel is stretched tightly over a flat surface, if you just drape a towel over a chair or something you will get folds that will have shadows in them, you need a very flat surface for a test such as this as you don't want subtle variations caused by a not perfectly flat surface. Regarding the choice of a black card. I fail to see what difference it would make. I'd be more concerned with using a lighter card as that may introduce flare. The main concern is to take a meter reading and then "place" the reading on zone I.
I agree totally although occasionaly I have given +1 development for an extremely low contrast scene.I use only the light metering portion of the Zone System to bring out selected shadows. I have never used the expansion or compression for film development since I do not need it with modern films.
I assume that, to rule out densitometer reading error, you've measured the density of a target such as Stouffer wedge and verified that the readings are fine.
An effective alternative to towel or black card is a diffuser mounted on the lens as a filter. Something that one uses to pre-flash film on location. For 35mm format film, Nikon ES-2 digitizing adapter is very convenient for these purposes.
I'd be concerned about the role played by the black target - reflectivity, surface sheen, etc. - and the metering technique for a reading from a black subject.
In an "idealized" world, a truly black subject would give you no reading whatsoever, no matter what the light levels are.
But as we aren't discussing telescopes and photographing black holes, it seems to me that it is better to use something like a grey towel with lots of texture instead.
A point I made 20 posts ago, and that was shrugged off as irrelevant by the OP.It isn't necessary to use a grey card - anything with a reasonable amount of reflectivity and some observable texture - a grey towel being an example - is a good subject.
You then place your reading from that subject on the Zone that you are seeking to target.
Mark,
My concern is that the card could be of such low reflectivity that it doesn't reflect enough light to give you a reliable meter reading.
A card that is way more than 4 zones darker than a mid-grey card.
Good question!
So are you saying AA's test procedure is basically flawed?A point I made 20 posts ago, and that was shrugged off as irrelevant by the OP.
To elaborate, I'd have an additional concern with the "black" target. Depending on the nature of the target (more likely to be printed than, e.g. carbon black), its reflectivity in the near-IR is not specified, and might be higher than in the "visible".
https://www.researchgate.net/figure...-and-dark-colors-with-variable_fig1_263017059
And, depending on the photocell in the light meter, (especially but not only CdS) it might have substantial response in the near-IR.
https://www.photrio.com/forum/threads/spectral-response-of-meter-cells.111298/#post-1472349
https://www.researchgate.net/figure...ral-response-to-solar-spectrum_fig3_237202290
These IR properties, combined, might result in underexposure of the target in the "normal" range 450-650nm. Which is a possible explanation for the anomaly seen by the OP.
What do you mean "technical error"? And what do you mean I am 3 stops off. AA wasn't expecting a density of 0.10 when rating it at its box speed. Later in the book he says he rates TX (Not TXP) at EI 200 so it's fair to say that his rating at EI 200 got him 0.10. The spot meter I used has recently been checked by a camera tech and found to be within factory specs. The camera was checked a year ago for shutter accuracy and I've never questioned it. The light source was constant.
AA says 0.09 - 0.11. I got 0.05 at EI 200 which is which is 1 1/3 stop from 0.09. Not 3 stops. (I don't know anyone who rates B&W film at its box speed.
Ralph, I'm sure you are familiar with H&D curves. The most important log value for photographers is 0.30 as it represents the important 1:2 relationship. To quote AA "An increase of 0.30 represents a doubling of opacity; on the log E scale of the H&D curve, an interval of 0.30 corresponds to a doubling of exposure - a one stop change on the camera, or a one zone change non luminance on the exposure scale.a transmission density difference of 0.9 stops have little to do with an exposure difference of 3 stops.
......
I should add that my Pentax spotmeter is a Zone VI modified meter.
So why are you asserting that 0.90 have little to do with an exposure difference of 3 stops? One stop is 0.30, 2 stops 0.60, 3 stops 0.90.
I agree totally although occasionaly I have given +1 development for an extremely low contrast scene.
I have found that giving a pre-exposure is a much more elegant thing to do with a high contrast scene.
I should add that in AA's later years at his Yosemite workshops he was saying that contraction, with the films available in the mid 1970s was not very useful. This came from a friend who did two of his workshops. He also picked up a 8 x 10 print of moonrise over half dome (printed by Ansel) for $20 that he recently sold for several thousand dollars.
Alan Ross is a really nice guy too.
Good catch. I fell for it too.I didn't quite get you. Isn't 0.10 - 0.01 = 0.09 and not 0.9?
Yes but usually you leave that whole a lot smarter than you entered it.Based on experience I would advise caution. The Zone System can become a rabbit hole...
Testing results that are outside the expected range, are most likely the result of an undesirable factor…
Whenever there is an expected experimental error, the next step is to evaluate the testing process.
That's a slightly insulting question, having developed films for 40+ years including 10 working in a pro lab. I live in Australia where it is the middle of summer although I'm not sure what the season has to do with film development temperature. I measure film developer 3 times, once just before it goes in, mid way through development and then after it is poured out, the drift is usually 0.5 Degree C.The error is kind of “significant”. It’s winter here and it’s hard for me to keep developer at 20-degrees C here. Wonder if the developer cooled down in the tank during the process
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