PDA

View Full Version : Question for Mr. Hicks


01-26-2010, 02:32
Dear Roger,

Firstly, let me thank you for the most excellent web-site.

I am struggling quite a bit with your assertion that "many of the best black and white pictures rely on deep, rich shadow detail, which in turn relies on plenty of exposure." This similar assertion can be found in your book "Perfect Exposure"

You see, I did exactly that but my black and white c-41 xp-2 super photos did not remotely resemble any of the photos in your B&W section. My photos have over-exposure characteristics, tones that are too light and an overall washed out look.

Now, my question is, are you suggestion that it is better to err on the side of over-exposure (so that depper tones can be capured as compared to shallow underexposure) and then to balance out the overexposure in the development process ?

Is this what is meant by "Expose the shadows, and develop the highlights ?"

Also, is this similar to your suggestion to rate B&W film speed slower eg. snap ISO 400 at say ISO 250 and adjust the development process as if it was a ISO 250 film ?


thanks

a fellow RFF member
raytoei aka englf

Vince Lupo
01-26-2010, 05:13
Not that I'm Mr. Hicks, but.....

This probably wouldn't work with a C41 film (though I could be wrong), however you could ask your lab to 'pull' the C41 development of your film to see what happens. Better to try it with a conventional B+W film, and it's something you could control yourself in a home darkroom.

Yes - 'expose for the shadows, develop for the highlights'. So, if you overexpose your film to bring in the shadow detail, and keep your development time the same (as though you exposed the film 'normally'), your highlights would be quite dense and lacking in detail. So, what you'd do is start by cutting your development time to compensate for the overexposure and to keep the highlights in check (the shadow areas of the negative are less affected by development than the highlights). I'd probably start by cutting your development time by 1/3, and go from there. This will vary from system to system (your 'system' consisting of your camera, lens, light meter, film, developer, etc). It's a sort of Zone System, at least for 35mm. It's all about 'place' and 'fall' (as in, 'placing' your shadows when you meter, and then seeing where the other zones 'fall' in the tonal scale).

The other thing you need to consider (if you're printing yourself) is whether you are using a condenser or diffusion enlarger. Due to the nature of the light, a condenser enlarger will produce more contrasty and sharp prints than a diffusion enlarger (assuming all other things are equal). So, you would probably have better luck with flatter negatives in a condenser enlarger, whereas a diffusioin enlarger would be more sympathetic to slightly more contrasty negatives (equivalent to a difference of one paper grade between a condenser and diffusion enlarger).

I've always found it better to have relatively flat negatives for darkroom printing. In printing, it's far easier to add contrast to a flat negative than to try and remove contrast from a bullet-proof negative. I could probably think of several methods for increasing contrast while printing, but maybe only two for removing contrast (and those aren't that great either!).

Perhaps Mr. Hicks can explain it much better than I.......Roger?

Roger Hicks
01-26-2010, 05:36
Are you printing the negs yourself? Wet printing or scanned? Machine prints may be light; wet prints made in your own darkroom can obviously be any density you like. Scanners can't 'see through' as much density as a wet print, so this can 'blow' the highlights, but they shouldn't 'blow' with wet printing.

The only way to get more shadow detail is with more exposure, and this pushes the rest of the exposure up the characteristic curve. The old 'expose for the shadows' is the basis of ISO speeds -- measuring the darkest area in which you want texture and detail, with a true spot meter or close-up reading -- and after that it's all approximations: (informed) guesses at brightness range, brightness distribution and lens flare. ISO contrast is based on these guesses.

No, I'd not change development time when rating an ISO 400 film at 250 as this is partly compensation for not using a spot meter and partly because (unlike Vince) I don't find that flat negs suit my enlargers very well (Magnifaxes with Meograde diffuser heads). I develop to give good tonality at grades 2 to 3, but with XP2 Super I often find that 3 to 4 is more useful.

I'll wait for answers to the opening questions before trying to help further. Vince's answer covers a lot of what's needed, except that I wouldn't try 'pulling' C41 film.

Cheers,

R.

degruyl
01-26-2010, 06:00
except that I wouldn't try 'pulling' C41 film.


I suspect you might be able to, though, with chromogenic B&W. You won't see the color shifts which are why (as I understand it) you should not process color C41 film this way. I really doubt that anyplace but a professional color lab will do it, though.

Oh, don't get me wrong: I never pull film. There is just plain no reason to. You can either recover in printing use less exposure. (For the rare case that EI400 is too much for a shutter max of 1/500, I carry ND filters).

01-26-2010, 06:14
Hi Roger and Vince,

Thanks for the quick reply.

I currently have my C-41 XP-2 Super film processed and printed at the 1 hour labs, this is one of the better labs with higher volume, hence fresher developers. They will not push or pull c-41 films. They do push and pull service for b&w films like the tmax, the ilford deltas etc.

In the book and in the web-site,there are many samples photos captured on XP-2 film, I presume that these are developed in-house and not sent to one-hour labs.

I am not limited to the c-41 process; I see myself eventually doing my own film development as part of the learning cycle, perhaps as early as later this year, but I will probably bypass contact printing and go straight to negative scanning and digital prining on my 4R canon selphy 30 dye-sub printer.

The picture which inspired me to ask these questions is this recent newsweek picture, and I am wondering how an increase in exposure can help me achieve this.


http://retro.ms11.net/uribe1.jpg

degruyl
01-26-2010, 06:22
How are you determining if the film is overexposed?

Are you looking at prints? scans? negatives? densitometer readings (yeah, I am kidding)?

If you are looking at prints or scans done by someone else, there is no way of knowing how they were made. Especially if they are bad. Assume for a minute that the prints are done by scanning and then printing, rather than wet printing. Some information is lost if the scan is set wrong.

XP2 does not have a color background (orange mask) like normal C41 film. If they set the scanner to expect a orange mask, and it is not there, I imagine that weird things happen when you subtract it out. XP2 is designed for printing in a normal B&W enlarger, and can be scanned quite well (as I understand).

Note: the above is specifically for Ilford chromogenic. Kodak and Fuji have the orange mask.

Vince Lupo
01-26-2010, 06:36
Oh, don't get me wrong: I never pull film. There is just plain no reason to. You can either recover in printing use less exposure. (For the rare case that EI400 is too much for a shutter max of 1/500, I carry ND filters).

It's interesting, but years ago in grad school we did a test of various 400 speed films, and found that they varied in terms of their 'actual' speed. 400 speed Kodak film is different from Fuji 400 film, which is different from Agfa 400 film etc, as each has their own definition of what '400' is. So I think it's a good idea to just work out our particular system, and what is best for us.

Sometimes (at least I've found this) you can't recover things in printing -- if there's no detail in your shadows in the neg because of underexposure, you aren't going to magically create some in the print by giving less exposure or dodging (of course, there are many times when you might not want shadow detail). Similarly, if your highlights are all blocked up in the neg because of overdevelopment, even a 1 hour exposure for the print isn't going to reveal any. Best thing is to make sure you have all the elements you need in your negative, because if it isn't there, it isn't there. Of course, I'm speaking of conventional black+white printing in a darkroom.

On a somewhat related note, in my Advanced Black+White Craft class taught by Craig Stevens years ago, he had us choose one negative that could fall down pretty easily on Grade 2 paper, and we came up with a 'cookbook' for printing variations. So I took 4 papers (Agfa Insignia, Agfa Portriga Rapid, Oriental Seagull VC Plus, and Zone VI Brilliant VC) and four developers (Edwal Platinum II, Edwal Ultra Black, GAF 120 and Dupont 54D), plus 4 toners (Kodak Polytoner, Kodak Rapid Selenium toner, Kodak Sepia toner, Berg Copper/Brown toner), and varied the dilutions, toning times, etc. We came up with about 268 different versions of the same print, and was a fantastic exercise in honing and refining your printing skills, as well as fine-tuning your personal 'system' (not to mention a very unique method of torture by Craig). Even after all that printing, I still love that one shot.

degruyl
01-26-2010, 06:53
[QUOTE=Vince Lupo;1245365
Sometimes (at least I've found this) you can't recover things in printing -- if there's no detail in your shadows in the neg because of underexposure, you aren't going to magically create some in the print by giving less exposure or dodging (of course, there are many times when you might not want shadow detail). Similarly, if your highlights are all blocked up in the neg because of overdevelopment, even a 1 hour exposure for the print isn't going to reveal any. Best thing is to make sure you have all the elements you need in your negative, because if it isn't there, it isn't there. Of course, I'm speaking of conventional black+white printing in a darkroom.
[/QUOTE]

No disagreement. I was merely saying that limited variation in exposure/development can be adjusted for in printing. Sometimes you get dense negatives, sometimes you get thin if you are not absolutely careful with each and every shot. I don't mean to imply that this is good, only that it can be somewhat adjusted for.

01-26-2010, 06:56
Degruyl,

I did several tests, same speed, same scenery but at different apertures, I would meter it first, then I would snap 3 pictures, one under, one normal, and one over. Remember, I am developing and printing this at the 1-hour labs. I would then compare the pictures. The overexposed would look lighter, brighter and flat. The underdeveloped ones and normal (metered ones) wold look better.

So back to my question, do we bring out the tonality in the development and printing phase ? If yes, does that mean that if I want to bring out the tones I should not have it C-41 developed or printed simply became the labs use default settings to develop and print.

degruyl
01-26-2010, 07:08
Degruyl,

I did several tests, same speed, same scenery but at different apertures, I would meter it first, then I would snap 3 pictures, one under, one normal, and one over. Remember, I am developing and printing this at the 1-hour labs. I would then compare the pictures. The overexposed would look lighter, brighter and flat. The underdeveloped ones and normal (metered ones) wold look better.


What this tells us is that your meter is working (possibly overexposing by default).



So back to my question, do we bring out the tonality in the development and printing phase ? If yes, does that mean that if I want to bring out the tones I should not have it C-41 developed or printed simply became the labs use default settings to develop and print.

C-41 developing is pretty standard. If they do a good job with color, the B&W C-41 should be good as well.

My suspicion is the printing for the normally exposed shots. That overexposed shots LOOK overexposed should come as no surprise. What you are not seeing is that they contain the most shadow detail. you can reduce the exposure of the highlights in development (and flatten the contrast, which gets you more tonal range). What you can't do is put detail on the negative that is not there.

kermaier
01-26-2010, 07:26
XP2 responds very well to overexposure by up to 1 stop with normal development, in my experience. Others are probably more knowledgeable, but something in me shies away from pull-proccessing C41 film.

Totally blocked highlights are, of course, possible, and impossible to print through. But barring that, there are plenty of printing techniques to deal with contrasty negatives, including use of graded papers, water bath development, split filtering with MC papers, etc.

::Ari

JoeV
01-26-2010, 07:26
If I may interject, the whole principle of over-exposing silver gelatin film and under-developing seems to work with more traditional types of emulsions (Tri-X, HP-5) in order to achieve a more dynamic tonal scale whereby under high-contrast lighting the shadows receive more exposure (due to purposely under-rating the film's Exposure Index) and the highlights are prevented from being too dense (being "blown out") by under development. The result is a negative that's able to fit the wide lighting range of the subject (such as a high-key landscape) onto the limited tonal range of film media. Then, in the printing of said negative, since you have the full tonal range of the scene available in the negative, it becomes easier to achieve a print with both rich shadows replete with detail, a tonally full mid-range and still retain some detail in the non-specular highlights.

All of this is predicated upon being able to control the development time of your silver gelatin film emulsion, so as to match your personal Exposure Index and choice of developer. You simply can't do this as well with the C-41 process.

If your choice is to stick with using C-41 B/W films, I'd recommend giving the film the exposure recommended by the manufacturer, with standard C-41 processing, and let it go at that. Just get as much of the scene's brightness range as possible to fit on the film's tonal range. And if you desire to print these negatives yourself onto silver paper in the darkroom, I recommend using Ilford's film, because the Kodak has the orange layer intended to guarantee that home darkroom users can't get a good print.

If you still want the most amount of control from your process, you have to shoot real silver gelatin film, process it yourself, and print it in your own darkroom.

The minilabs are developing C-41 to a standard time, scanning the negatives, and then the digital files are used to expose RA-4 paper using the laser Noritsu or equivalent machine; you aren't going to get the same quality print, especially the highlights, with such a process.

~Joe

degruyl
01-26-2010, 07:33
Thanks, Joe. That is pretty much what I was trying to say without running out on a limb.

payasam
01-26-2010, 08:16
I've done my own film processing and enlarging, of course, but far more of my work has been done by labs which also handled the work of other photographers. They used standard MQ developers and the same time-temperature processing for all brands and speeds of B&W film. Barring obvious exceptions, the results were satisfactory. The extremes that were encountered depended on one variable, exposure.

With lab-processed chromogenic film, I suggest that exposure is the key. If exposure is correct, most negatives will have the correct density and tonal range. Where the scene demands special treatment, varying exposure alone should be adequate.

Vince Lupo
01-26-2010, 09:35
On another related note -- I remember in my Advanced Color Craft class, we tested the exposure 'limits' of C41 color negative film. I found that you could overexpose color film as much as 2 stops, and still get a good print. True, the contrast will go up, but the print will still look relatively good. Don't know if this would apply to films like XP2 or 400CN.

john neal
01-26-2010, 10:35
Vince,

I normally rate XP2 at 200 for use in a Barnack, and find that the negs from a minilab are generally fine. Scans can be a different matter, often being obviously overexposed, or with a colour cast. I just rescan using viewscan and a profile that I put together myself.

Having dabbled with C41 dev at home, I would not suggest pulling this sort of film - for me it just went muddy. Esentially, the more I overexpose XP2 (within 3 or 4 stops) the better I like it - and I'm not looking for Bill Brandt levels of contrast!

Obviously wet printing would be better, and much more controllable, but I don't have the sapce for a darkroom at the moment (it's in boxes in the loft).

Bike Tourist
01-26-2010, 11:08
Of course, the idea is that you want to maintain the shadow detail in negative films and preserve the highlight detail in positive films (slides, transparencies). Back when I shot all film my rule-of-thumb, subject to modifications, was to underexpose slides by 1/3 stop and overexpose negatives by 2/3 stop. This seemed to work well for someone like me who didn't overly obsess over exposure.

These days, I shoot BW400 at 250 and live with it — commercial C41 processing and PS on my computer.

Roger Hicks
01-26-2010, 11:48
An enormous amount depends on metering technique. Normally, when rating an ISO 400 film at EI 250, most of what you are doing is compensating for broad-area metering. Use a true spot meter (1 degree, NOT in-camera 'spot') and you can use the full ISO speed. Somewhere I remember a quote from Ansel Adams that once he started using a spot meter, his exposures went up by a full stop. Dick's (Bike Tourist's) 2/3 stop rule for negs agrees perfectly with this.

I think that the poor tonality, lightness and blown highlights is totally down to machine printing. A useful trick we used to tell account execs to use in the 70s was to shoot an absolutely 'average' scene for their first frame, with half the ISO set on the meter (this was before bar-coded films), then we'd have the lab lock on that for the rest of the film. Worth trying. ('Account execs' because I worked in an ad agency and they'd all bring us their films to develop. We sent them out, of course.)

Most of our C41 is trade processed, ideally pro lab but plenty of minilab too. The only reason we process our own C41 now is that it's quicker and you get a water wash.

Try ordering an enlargement of one of your negs: a (fairly) cheap way to see what can be done. DO NOT give them the machine print (or they'll use it for a ref): just the neg strip with a note of the one you want.

@ David (Degruyl) and Ari and John: I completely agree there's no sense in pulling C41, though as you say,it's possible. David: how much variation did you find in speed with the 400 films, and how were you testing? If you plot two D/log E curves and they're reasonably congruent across the ISO speed reference range, speeds are the same. I assume that was your methodology? Or were you working with prints, where curve shape has more effect?

@ Joe: My only argument with anything you say is that as I say above, the extra exposure is to compensate for metering tehnique. With D/log E curves I found that XP2 was 1/3 stop faster than Kodak's ISO 400 (there is no ISO standard for chromogenics, as far as I am aware) so even using box speed is 1/3 over and I'd go more over than that. You lose sharpness but grain gets finer.

@ Mukul: Well, yes, quite, though seasoned developers (as you're my age, you're old enough to remember those) do indeed lose about 1 stop in true ISO speed, so they normally overdeveloped a bit to make up for it...

Cheers,

R.

01-26-2010, 15:18
thank you people. let me slowly digest the wealth of knowledge here.

cheers!

raytoei

degruyl
01-26-2010, 15:34
. David: how much variation did you find in speed with the 400 films, and how were you testing? If you plot two D/log E curves and they're reasonably congruent across the ISO speed reference range, speeds are the same. I assume that was your methodology? Or were you working with prints, where curve shape has more effect?



Sorry, Roger, I forgot to trim my name from the quote: that was the OP talking about testing.

(I think this is what you are referring to). I have never used XP2, I just know a bit here and there. I was talking general terms about exposure and C-41.

Trius
01-26-2010, 17:05
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.

payasam
01-26-2010, 18:24
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.

Vince Lupo
01-27-2010, 00:45
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.


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.

Roger Hicks
01-27-2010, 01:10
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.

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
01-27-2010, 01:54
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!

Roger Hicks
01-27-2010, 02:03
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.

Vince Lupo
01-27-2010, 02:22
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.

Sparrow
01-27-2010, 03:10
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.

Vince Lupo
01-27-2010, 03:19
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.

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
01-27-2010, 03:38
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.

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
01-27-2010, 05:59
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
01-27-2010, 06:04
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.

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
01-27-2010, 06:09
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).

My sentiments exactly!

So the moral of the story, Raytoei, is to not overthink things - otherwise you might miss the shot!

Roger Hicks
01-27-2010, 06:12
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.

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.

john neal
01-27-2010, 12:31
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.


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
01-27-2010, 17:50
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.

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
01-28-2010, 08:21
Gotcha -- I now understand what you're talking about. Sorry for the misunderstanding.