Trius
Waiting on Maitani
First things first ... Is your meter calibrated/accurate? Roger alluded to metering technique ... how do you meter?
Film speed, as referred to in this thread, is defined my shadow detail. What you want is barely detectable tonality in a Zone I exposure.
Getting prints done by a bog standard lab on standard colour print material makes this whole exercise pretty difficult.
Film speed, as referred to in this thread, is defined my shadow detail. What you want is barely detectable tonality in a Zone I exposure.
Getting prints done by a bog standard lab on standard colour print material makes this whole exercise pretty difficult.
payasam
a.k.a. Mukul Dube
John, I have a couple of rolls of XP2 Super sitting around. Al Kaplan posted them to me the day before he went into hospital. I was thinking of doing the first at 320 and the second, depending on results, at 250. But you give the film a full stop, so I wonder if I too shouldn't expose at 200. I'm afraid your note on scanning the negatives is not clear (accidental pun) to me.
Dick, when I worked with slide film, I under-exposed by half a stop: and the results showed that, with incident light measurement (reflected light reading off the palm of my left hand plus one stop) that was correct. However, I exposed B&W film at the rated speed: with the exception of ORWO NP22 and NP27, which needed slightly more exposure.
Dick, when I worked with slide film, I under-exposed by half a stop: and the results showed that, with incident light measurement (reflected light reading off the palm of my left hand plus one stop) that was correct. However, I exposed B&W film at the rated speed: with the exception of ORWO NP22 and NP27, which needed slightly more exposure.
Vince Lupo
Whatever
Zone I? Don't know if this is what you mean, but Zone I is the blackest black in a print (no detail), so if you want shadow detail (like dark hair), you'd want Zone III. Zone V is a middle tone (18%) grey, and all light meters are calibrated to that. Whatever you point your meter at, it wants to make it Zone V. So, if you're using a hand-held reflected meter (as opposed to an incident meter), and you want good shadow detail, measure your shadow detail, then place it in Zone III (basically adjusting the meter reading down by two stops), see where your highlights will fall based on that reading (snow would be Zone VIII, for example), then calculate the development time you'd need. Of course, this is assuming that you're shooting the whole roll of film under the same lighting conditions, and this is the problem with trying to apply the Zone System to 35mm film. But, basic principles of the Zone System can be utilized, and can definitely lead you to better negs in the long run.
Meter calibration can be a challenge -- this is what I mean by tailoring your 'system' to you. Your meter, your camera, your camera's shutter, the film you're using, developer etc etc is different than what I'm using. So, you need to figure out what works best for you, and what you need to do with your system to get the results you're wanting.
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Roger Hicks
Veteran
Dear Vince,
I agree with everything you say except the bit about 18% grey.
The average reflectance of an outdoor scene was established at 12-14% by research done by Kodak in the 1930s, and never bettered. This is the calibration of most broad-area reflected-light meters, while 18% grey is a Munsell mid-tone -- the tone that most people will pick as a mid-grey if shown a wide range of different greys, from black to white, and asked to put them in order.
This error has appeared countless times in print: I was even guilty of it myself until I learned better.
Cheers,
R.
Vince Lupo
Whatever
Um, don't know about that (Though I must say Roger that I am enjoying this discussion!). Every photo book that I've ever read has quoted 18% grey as being the geometric midpoint from black to white, or a full-textured middle grey. Ansel Adams, Richard Zakia, and every tech teacher I ever had referred to 18% grey. Kodak produces an 18% reflectance grey (or gray) card. Yes, I have heard about calibration to 12-13%, but this goes back to what I was saying about the film differences between the companies, and the need for each of us to calibrate our personal 'system'. I remember in 1st year undergrad tech class at Ryerson, and the professor asked us to bring in our light meters for 'calibration'. As you can imagine, all of our meters were all over the place, but it didn't really matter all that much - as long as we knew what OUR meters were doing, then we'd know how to adjust accordingly. Same goes for the shutter in your camera, particularly if you're using a camera with a mechanical shutter -- how many of them are delivering a 'true' 1/60th of a second? Many factors, and when each of us has so many elements involved in our systems, we're all slightly different.
Oh heck - just look at the scene, guess the exposure and shoot...we're probably thinking too much!
Oh heck - just look at the scene, guess the exposure and shoot...we're probably thinking too much!
Roger Hicks
Veteran
Dear Vince,
Yes, it's a mid-tone. No-one disputes that. But 18% is NOT the average reflectance of a scene, and it would be perverse to calibrate a meter to something that is about 1/2 stop darker than average reflectance.
Which is not to say that meter manufacturers are never perverse...
Cheers,
R.
Yes, it's a mid-tone. No-one disputes that. But 18% is NOT the average reflectance of a scene, and it would be perverse to calibrate a meter to something that is about 1/2 stop darker than average reflectance.
Which is not to say that meter manufacturers are never perverse...
Cheers,
R.
Vince Lupo
Whatever
Yes, I think that's it. I don't think these meter or film companies are talking to each other, and their respective ideas of what a 'mid-tone' is are probably not shared by one another.
However, I will quote Ansel Adams on page 33 of 'The Negative':
"The 18 percent reflectance value is mathematically a middle gray on a geometric scale from 'black' to 'white', and it is this value that the meter is calibrated to reproduce in the final print. This 18 percent reflectance is a fixed key reference point, and functions like the 'A' of the musical scale as a universally recognized basic value.
Knowing that the meter is calibrated to reproduce this value (But as I pointed out in an earlier post, all our meters can be slightly different!), we must remember that making a reading from ANY single luminance surface in the subject and using that reading to determine exposure will cause that surface to be reproduced as a middle gray in the final print. If making we make a reading from a 'black' surface in the subject, we can expect it to reproduce not as black, but as a middle gray in the print. Similarly, a reading from a 'white' subject area will yield an exposure that reproduces that area as middle gray. The meter, again, has no way of knowing what it is reading and 'assumes' that it is an average middle value comparable to that of the 18 percent gray card."
Now, this was certainly written a number of years ago, and I don't know if the 12-13% had become an accepted figure during Adams' lifetime. But if it had, he certainly wasn't adhering to it, or so he seems to indicate.
However, I will quote Ansel Adams on page 33 of 'The Negative':
"The 18 percent reflectance value is mathematically a middle gray on a geometric scale from 'black' to 'white', and it is this value that the meter is calibrated to reproduce in the final print. This 18 percent reflectance is a fixed key reference point, and functions like the 'A' of the musical scale as a universally recognized basic value.
Knowing that the meter is calibrated to reproduce this value (But as I pointed out in an earlier post, all our meters can be slightly different!), we must remember that making a reading from ANY single luminance surface in the subject and using that reading to determine exposure will cause that surface to be reproduced as a middle gray in the final print. If making we make a reading from a 'black' surface in the subject, we can expect it to reproduce not as black, but as a middle gray in the print. Similarly, a reading from a 'white' subject area will yield an exposure that reproduces that area as middle gray. The meter, again, has no way of knowing what it is reading and 'assumes' that it is an average middle value comparable to that of the 18 percent gray card."
Now, this was certainly written a number of years ago, and I don't know if the 12-13% had become an accepted figure during Adams' lifetime. But if it had, he certainly wasn't adhering to it, or so he seems to indicate.
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Sparrow
Veteran
I think Adams would be talking of a spot meter, not a reflective one.
Obviously spot and incident meters would need to be set to perceptive mid-grey.
Obviously spot and incident meters would need to be set to perceptive mid-grey.
Vince Lupo
Whatever
Well, a spot meter is a reflected light meter, albeit one with a much narrower angle. But yes, you'd get a more 'fine-tuned' reading by using a spot meter.
Sparrow
Veteran
With the zone system the whole system is calibrated to make a mid grey object mid grey in the print, your "average" user of a reflective meter just wants’ to point it at an “average” scene or their girlfriend’s face and use that setting, hence the manufactures set them to do just that.
Vince Lupo
Whatever
Very true -- and if you spend too much time metering this and that, and calculating and tabulating and placing and falling, your girlfriend is probably just going to walk away.
degruyl
Just this guy, you know?
Which is extraordinarily inconvenient when you are trying to take her picture.
(Sunny 16, or quick external metering, mainly ignore in camera metering. I was trained by my Mamiya 7).
Vince Lupo
Whatever
My sentiments exactly!
So the moral of the story, Raytoei, is to not overthink things - otherwise you might miss the shot!
Roger Hicks
Veteran
Dear Vince,
I'm not sure that the highlighted portion has any meaning whatsoever, and even if it does, we are dealing with the psychology and physiology of vision, not with mathematics. Merely because the Blessed Ansel wrote it, doesn't mean it's true. He was a great photographer long before the Zone System, but others did all the basic research, and for my money, quite a few explained sensitometry better too.
The world's first commercially successful spot meter (SEI Photometer) didn't even have a mid-tone index because it's a complete waste of time in a spot meter except in the rather artificial world of the Zone System. After all, no speed system is based on a mid tone. They're based on shadow values (negative) or highlight values (transparency and digital).
The only other thing that matters, after you've metered either the highlight or the shadow, is the brightness range, i.e. the other index. The Zone System was designed long after the basic reseach on the D/log E curve was done by Hurter and Driffield in the 1880s and rather after the basic research on average reflectance and the First Excellent Print was done at Kodak in the 1930s.
The Zone System is an oversimplification of sensitometry in some ways, and an overcomplication in others. The only really useful bit (which is a work of genius) is arbitrarily chopping the brightness range of a print into Zones. The real world, of course, has no Zones, which exist only in the photographer's mind until the film is exposed and processed, and the print made.
Quite probably the 'mid-tone' for a spot meter is an 18% grey, because 18% is an object of worship for Zonies. But as far as I recall, if you look at the instructions for using a grey card, you don't point it straight at the camera, but angle it between the subject/camera axis and the subject/principal light axis. This gives about 12%... And before the grey card, in 1940, Kodak was recommending a similar procedure with (Kodak-yellow) paper packets...
The truth, I am convinced, is that the neg-pos process is so inherently flexible that it saves the negatives of an awful lot of people who think they are being far more precise than they are.
EDIT: I've put the last para in bold because I'm sure it goes to the heart of the whole debate.
Cheers,
R.
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john neal
fallor ergo sum
Mukul,
What I meant to say wa that I calibrated my scanner and Vuescan to XP2 film. This is then saved as a "profile". If you google around for your scanner / software combination, you will probably find out how to do this. It normally involves canning a piece of clear, exposed & processed, film to give (effectively) a base-fog level, and comparing that to a fully exposed max density black.
Does that help?
Trius
Waiting on Maitani
I know what Zone I is, what Zone III is, etc.... not being combative, just stating that I know what I'm talking about.
See Zone VI Workshop for an explanation of shooting Zone I exposures (~.08 - .10 over base density/fog) to determine personal/working EI. Once that is determined, then Zone III readings for dark shadow detail is an important technique in making "real" photos, yes. Not the only way, of course.
Vince Lupo
Whatever
Gotcha -- I now understand what you're talking about. Sorry for the misunderstanding.