Testing procedure clarification

[sg_adams]

Can someone varify that I am interpreting the film speed testing procedure

correctly.

I have done some testing already, but reading a lot of posts and re-reading my

book has left me a little confused, and I would like to make sure I am going

about it the right way.

I am metering my target gray card for zone V placement for the first

exposure.

Then make a box speed exposure with the target placed on Zone I.

And here's where I am unsure. The way I read it,and was doing it, was to

simply make the series of 1/3 stop plus and minus exposures. But then I got

to thinking that may be wrong. Seemed too easy. Should I be re-metering and

placing for zone I at each 1/3 stop change as if I were using a third stop

different ISO film also? Or do I continue as I have been doing, and stop up

or down from the original zone I placement (unless the light changes), thereby

adding more or less exposure?

 

thanks

[lex_jenkins]

Not to detract from the inarguable merits of careful metering, exposure and development, what is your goal and what kind of equipment are you using? For example are you using sheet film or roll film?

 

Also, if your goal is to achieve the most accurate possible exposures, you should be aware that shutter speeds and f/stops vary considerably, sometimes more than 1/3 EV from the nominal setting. These vagaries can conspire to thwart your efforts.

 

Alongside your efforts to master metering, exposure and development, don't overlook the equipment itself. Until you know for certain what your equipment is doing, trying to pin down the Zone System and achieve accuracy as fine as 1/3 EV will likely result in frustration.

 

Finally, and I fully expect rebuttals to this notion, I don't see any point in trying to apply the Zone System in the strictest sense to 35mm and even medium format photography. The culmination of the Zone System is individual development of each frame to suit the conditions - light, metering and exposure. Unless every frame of roll film is exposed identically - same lighting, same exposure bias - it makes good sense to simplify procedures. Use good exposure practice, which usually involves giving a little more exposure than the rated ISO would indicate, and avoiding overdevelopment.

 

Unfortunately this common sense approach has been somewhat trivialized because it, too, has been preached as dogma and with near rabid fervency equal to the most doctrinaire of Zone System advocates. The fact is, it's neither a religion nor a lazy photographer's approach. It simply works.

[sg_adams]

Well, you did everything but address the question, which relates to finding a proper film speed.

I am going to test some sheet film, and some roll film.

Ans I have been known to shoot extra frames as well as bracket a whole roll of 120 film on one composition, and glad of it. Film is cheaper than gas now and I tend to hike quite a bit after I park the car, so I tend to lean towards getting something worth while besides four thousand mosquitoe bites and sore feet. Just a thought.

[lex_jenkins]

"Well, you did everything but address the question..."

 

I'll be sure to forward your concern to our customer service department in India.

[hitam_jantung]

What Lex was too polite to say is that you're wasting your time with your testing regime, and you'd be far better off shooting at box speed, developing for the recommended time, and scanning or printing on VC paper. FAR better off. Nothing you've proposed doing will make your exposures more accurate than what I've suggested, and will in all likliehood make them less accurate. I hope I've not been too obtuse.

[rick_jones5]

If you get confused as to the effective film speed as you bracket around your initial Z1 placement you can simply change the film speed on your meter in 1/3rd stop increments, meter your target, set your exposure and then reduce that setting by 4 stops. Everyone involved with photography for an extended period devises some way to determine an appropriate E.I. along with development times for their preferred film and developer combination. What always bothered me about testing for Z1 was that I never ever meter and place a reading in Z1. I much prefer to meter and place for Z3 then examine the negatives and prints carefully to determine if I got the shadow detail I was looking for. If not I adjust my E.I. or metering technique. If your approach gives you the results you want in the final output I believe you are one step ahead of those that shoot at box speed and develop per manufacturers suggestions for no other reason than "but that's what Kodak says". So I say testing is good. Just be guided first by real world photo results.

[Vlad Soare]

Here's a testing method posted by another member, which is probably the best you can do without a densitometer:<br>

<a href=http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00NUY8>http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00NUY8></a>

<br><br>

Unless you use either large format or medium format with multiple film backs, the zone system is not really applicable. However, I think it's important to find the true speed of the film with your camera, your lightmeter, your technique and your developer, and Keith's method is just what you need. :-)

[Vlad Soare]

I also second Rick's opinion about zone I placement. Metering for zone II or III would make more sense, since that's where you'll want your blacks to end up anyway.

[rodeo_joe1]

Don't just look at the box for the "box speed". Kodak issue extensive data sheets and sensitometric curves for all their films, and these are far more useful than anything you're likely to find out for yourself. Not unless you're willing to invest copious amounts of time and money in equalling the facilities and methodologies of Kodak's laboratories. They don't just make this stuff up you know!

 

For example: The old T-max100 was shown as having a rather strange curve when developed in D-76. I was curious, and did my own sensitometric tests on this film/developer combo. After honing my testing methodology and aquiring and calibrating a densitometer, I was finally able to plot a reasonably accurate characteristic curve; and guess what? It was practically identical to the one published by Kodak. This was just in time for Kodak to withdraw the old T-max100 and replace it with the current 100T-max. Humph!

 

If the results you get differ wildly from those published by the film manufacturer, then you should check the simple things like the accuracy of your thermometer, lightmetering method and shutter speeds, rather than fiddling about with EI values and needless sensitometry.

 

Honestly SG. You're far better off using your time and film to take real pictures. We've all been there - blaming mediocre results on improper exposure or developing. The reality is that even one stop either way really doesn't make all that much difference to modern B&W film, and a bad composition is still going to be bad, even if it's perfectly exposed.

 

It would help if Ilford labelled the x axis of their film curves in lux-seconds, rather than the meaningless "relative log exposure" though. And gave us a family of curves like Kodak.

[profhlynnjones]

Hi SG

 

email me and I'll send you all the data you'll need for properly evaluating films and developers. There really are world standards, the differences for use have to do with the real world and themanufacturer's sterile world.

 

Lynn

[sg_adams]

Thanks for all the responses. I will write more this evening when I have more time to evaluate all that has been written.

For what it's worth, I think a person can learn a lot from looking at film without an expensive densitometer, esspecially in the low values, and that is my first goal of coarse. WIth roll films I wish to be able to simply make better well thought out exposures, and actually apply zone system work to important shots on 120. 35mm is pretty much as Lex suggests already, but I think much can be improved by using a more appropriate film speed and development.

As for sheet film, someone gave me a 4x5 enlarger so I want to start getting ready to make higher quality sheet film exposures. I have a Pentax spot meter now and intend to individually test any lens that I choose to take on the road. Which includes shutter speed cards, development and exposure adjustments for contrast and flare (I use a c.1916 Cooke 7" lens sometimes) and all the other time consuming things Ineed to do to prepare for the summer trip season. I don't intend to think I will be the Zone Master in a few short months but I think the effort will be well worth the trouble considering the trouble I go to to get to the places I tend to go.

thanks again,

Stephen

[tripanfal]

Lex, You owe me a keyboard. I blew soda out of my nose.

 

worth repeating below...

 

"The reality is that even one stop either way really doesn't make all that much difference to modern B&W film, and a bad composition is still going to be bad, even if it's perfectly exposed"

[hitam_jantung]

Testing is not bad per se, but the tester should be realistic about the limitations of his regime, and how his results will compare to the testing done by the manufacturer. The regime proposed by the OP is very imprecise, and is more likely to deviate from a film's true speed than to improve on the manufacturer's rating. The "real world" factors that demand compensation are better managed by testing individual components, such as shutters, with an appropriate testing device to determine the actual deviation, and compensating for flare is as much a matter of taste as it is a quantifiable value. Given the highly evolved testing methods practiced by film manufacturers, film speed testing is usually a waste of time, especially considering how easily exposure is evaluated in a scan or print, and any needed corrections made on that "real world" basis, which at least brings the printing process/material into the equation. The real value in materials testing is to scale the negative to the printing paper over a range of exposure conditions, which is in itself most useful when using sheet film and graded papers. For those of us using roll film and scanning or printing on VC papers, these convoluted testing regimes are very unlikely to secure improvements over a simple approach of shooting at box speed, developing normally, and compensating for abnormal exposure conditions in printing. If you want a higher degree of precision and control, you'll have to commit; shoot sheet film, buy a sensitometer, a densitometer, a calibrated step wedge, and a shutter tester, and learn how to use them.

[lex_jenkins]

SG, by all means, I really do encourage you to explore the Zone System. I did in college and it was a rewarding experience. Some of my best photos - at least in terms of exposure, etc. - were taken during that period.

 

If you're using sheet film, have the spotmeter, understand the vagaries of equipment that conspire against us (don't forget to check the accuracy of your shutter speeds and f/stops - they can be off considerably from the nominal settings), and have the time and patience, you should at least explore it.

 

I no longer have the patience and don't shoot sheet film anymore, but I don't regret the time I spend on the Zone System.

[keithostertag]

Hello SG-

 

If you are interested in doing it, film testing can be quite revealing and rewarding. Finding your own personal EI now will save you lots of time and hassle later. So I encourage you to read the link to Keith Lubow's method as given above, or develop your own method based on your readings. Here are a few pointers:

 

Change only one variable at a time.

You may be surprised how much agitation methods affect film densities- consistency is very important.

You might consider starting with the print- choose a specific print size, paper type, and developer. Determine your minimum enlarger exposure time for that specific print size with that film (a processed but unexposed section) for maximum black. Then alter your film exposure to suit your shadow detail requirements at that enlarger exposure time. After that you can vary your film processing times to get highlight detail at that same enlarger exposure time. Do this first, then you can start exploring further refinements.

 

For instance, for my personal setup I have found that to print a 14x14 inch print from my 2 1/4 x 2 1/4 negatives the enlarger head height is 30 inches and the enlarger exposure is f8 for 30 seconds. It turns out for me that this is close for several different films. If I change film type or agitation method or developer for any reason, I keep the above stable and see how far off the print values are, then alter the film development accordingly. This of course assumes similar images in similar subject brightness ranges, on the same grade paper, typical with my use of roll film. Doing it this way means I spend far less time in the darkroom printing, and I don't need a densitometer.

[rothelle]

The Zone System is a simple guide to photographic control. It's a wonderful tool I use to calibrate all of my photographic equipment. I'm not only talking about my camera, meter, shutter, f/stop and film speed. It has also up my skills in the darkroom from the time I push the shutter to the print I now have drying. A great book to get a clear and easy understanding is a book The Practical Zone System by Chis Johnson. You get out in the field shooting fast and having fun at the same time learning it.

[dave_wilson1]

The film speed is what's on the box. Your testing is a test of your equipment and how it behaves with that film, that's all. What are you trying to do match zone 5 print with the grey card? What book are you using exactly?

In reality spot meter the area you're exposing for, decide what zone you want that area on and adjust your camera based on the box speed of the film your using. Develop and print everything using your normal procedure and record your results in a notebook. There, your done, you don't need all this other information unless you own very high end precise developing equipment. Except now you know what you really need to know, if your equipment (specifically your meter) is "up to speed" with your film. But you need to test all the cameras and lenses you're going to use if you don't want surprises.

[sg_adams]

Hum, someone above suggests I am wasting my time and should shoot at box speed and develop normaly.

Let's see, Acros shot at box speed and developed normaly will blow out the highlights in open sun, an easier filmto tame than TMX, but not forgiving either. TMX at box speed and developed as recomended isn't even printable.

FP4 doesn't perform well at box speed and I never had any good negs with it until I started shooting it at 64. TMY works OK at box speed but will also blow out the highlights if not careful, even in open shade. At least that was my experience last summer. When I started overexposing and pulling the development I got much better results.

I do like HP5 at box speed and standard development and use this film a lot with vintage optics and ussually bump the development time a little if using uncoated optics.

I shoot medium and hand held medium and large format sometimes so I will still use box speed on 400 films which I have already worked out my development times as suggested above. I also calcualted my own times for Delta 3200 for D-76 1:1 because I didn't like the results with stock solution, much better for the sharp grainy look. But for sheet film and 120 roll film projects that take me into the mountains and deserts in conditions that rarely favor box speeds and standard development, I thought a little work at home might render some more exciting results.

But for dialing in some film speed and zone type work, I intend to pick one film and one developer for sheet film, probably TriX and HC110, for ease and there is already a ton of info on it and I tried a while back and really liked it. I will probably try a rollor two of the new TMY in the HC 110 and D-76, and compare the grain but intend to pick and stick by the end of March.

[sg_adams]

So far it seems a lot of folks are suggesting I am wasting my time. Hum? I don't think so. Since I plan to run all preliminary testing with one lens (one I have used extensivley at home and in the field) , and then cross check every lens I intend to work with, make shutter speed cards and copies, have already done contrast comparisons for more than thirty lenses, service and repair my own shutters, repair, refurbish, and rebuild my own and other's cameras, I think I can at least apply a little bit of the mysterious zone system to my list of things to do. Not my problem if others tried, got frustrated with it, or don't want to invest the time, because that is what I am hearing. Don't do it. If I can look at the TMY test exposures and easily pick out the card target that falls on what I know my printer will register at Zone I, and then go to the development snips and see that my Zone VII target would print too low in value (Zone VI), I'd suggest that I am already pretty close to what I am after with TMY provided I am satisfied with the mid tone values after some more testing. I have been dealing with poorly exposed negs for a long time(box speed, suggesteddevelopemtn times and tempsetc...), and using the same enlarger, and have a really good idea how it and my EL lenses work. So that is being taken into account when I am examining my film (as a system). It was suggested above to try working at a higher value than zone I and I actually used the last couple exposures of each 120 roll I used to do just that and it made a good example for comparison. Jeez, I am just finally trying to make a start here at this and almost all I have recieved are negative comments from folks who don't seem to think the ends will justify the trouble, or don't do Zones anyways. Gosh, don't try anything, you might succeed? So you are telling me I can't apply film testing and zone system techniques because I don't have thousands of dollars of specialized equipment and modern photographic paraphenalia? That I can't look at a negative and have any idea that what I am seeing is better or worse, will print better or not than this or that?

Why don't I just quit; it would be less trouble, or better yet, get a digital camera? All I needed to know was if I was approaching the personal film speed test properly. I don't remember asking whether or not it was a good idea, or if I would get better results. I think I will be able to decide that for myself over the next couple months. A person would think a few folks fear another Zone System fanatic will be born and start preaching against any other style or approach. Don't worry, I am much more ornery than that.

A big thanks to the couple people who offered to answer my question and posted some links and recommended reading, appreciate it.

[skygzr]

SG -

 

I think what some folks are trying to imply is that you can spend a great deal of time and effort testing film for a fairly small return. Exposure and development is really pretty simple. I did exactly what you're doing and here's what I learned.

 

"Expose for the shadows and develop for the highlights" really is good advice. In practical terms, this means that I expose most films at about a stop slower than what's on the box (Acros 100 gets 50 on the meter).

 

I did use a densitometer to peg development time, but you don't need one. A light table and a step wedge can get you pretty close. There's a generally accepted density value for Zone VIII which can help determine development time (I always forget the number). Compare the Zone XIII negative (on a light table) with the step closest to that number. If your Zone VIII is too dark, back off on development (try nine minutes instead of ten). If its too light, increase a little.

 

If you're getting blown-out highlights (at any reasonable speed) you're probably over developing, not overexposing. A modern emulsion like Acros has lots of headroom. A little overexposure is perfectly OK.

 

Some people insist that if you expose a 100 speed film at 50, you MUST cut development time. There may be cases where that's true but in general I disagree. Everything just gets placed a little higher on the curve. Try this: put your camera on a tripod and set the meter for box speed. Take a series of pictures "overexposed" in half stop increments. Go WAY over the top. Make prints...you'll be amazed at how far you can go before things get unusable. Remember, if your highlights are ALWAYS blown out, its probably development, not exposure.

 

Speaking of the the customer service desk, I hate it when you get someone who tells you his name is Robert, and it's clearly Ramesh. I have no problem talking to Ramesh....just don't lie about it.

[dave_wilson1]

SG, I really think you are missing what people are trying to share. My point is two specific things. FACT the film speed is created and tested by the manufacturer and is what it is, it will not change until they change it. If you didn't get the right results you screwed it up, not them. I don't ever blame the film, I blame me....YOU need to understand how your equipment behaves with that particular film and take careful notes and adjust your exposure and developing accordingly.. FACT, UNLESS you are using very precise developing techniques with absolutely uniform agitation and electronic temperature control, such as an automated expensive machine, all this testing crap is useless, period. Just some simple tests as I discussed above will cover the deal. Also, you never did ever indicate which book you're using and what test you're doing, how are we supposed to know? There are thousands of quacks who have written about photography, just like we're doing now. OK, Cheers, go have a beer.

[rodeo_joe1]

Zone XIII! What's that whirring noise? Oh, that's it. It's a certain Mr Adams revolving in his grave at high speed.

 

The Zone system only describes the tones on a PRINT, and since Zone X is pure featureless white paper, you can't get any higher. Adams shows and describes "values" 0 to XII when referring to negative exposure. He's very careful to save the term "Zone" for describing print tones. And anyway, what film is capable of holding a 13 stop range (if that's what zone XIII is supposed to mean)? Not many I suspect. Now let's see, 2^13 is ummm, 8192. Does anyone seriously believe that there's a camera and lens combination out there capable of delivering a flare factor that comes anywhere close to 0.0122%? If so, you're dreaming. Wake up!

 

Even if you could get that brightness range accurately onto film, you'd have to pull development to a CI of around 0.3. Resulting in a print flatter than roadkill on a Bank holiday.

 

The Zone system, as described by Ansel Adams, is an excellent tool for helping to previsualise an image, and as a guide to the technique used to get that image onto film. It's an elegant and fairly simple elaboration of the old adage "expose for the shadows, develop for the highlights".

 

The zone system (small z) as now perverted and espoused by advocates of endless testing is a pure nonsense, totally divorced from any sense of reality or aesthetics.

 

It should be remembered that Adams invented the system before sensitometry as a science was fully formulated, and before an internationally recognised system of film speed rating was adopted. It also helps to know that Adams was a concert pianist, and you can see the strong relationship of the Zone system with the musical scale. Long live the Zone system (with a capital Z).

[sg_adams]

Thanks Joe. You pretty much summed up my philosophy about the whole thing. I don't understand all this extra stuff folks have written that basically is counter productive. Easy, "expose for the shadows and develop for the higlights". Still have to test the film and get the developing dialed in. I'll think twice before I ask any more questions here.

[Vlad Soare]

Joe, that "XIII" was most probably a typo. I bet Kevin meant zone VIII. :-)

[Vlad Soare]

I don't quite agree that the manufacturer's speed is always correct and that testing is a waste of time. My experience has shown me otherwise. If I photograph the same scene on three different films, trying to place a black subject in zone II (to be almost black on paper, but with a slight hint of detail), I can achieve this with Tri-X rated at ASA 400, I can also achieve it with Foma 100 rated at ASA 100, but I can't achive it with FP4+ unless I rate it at ASA 50. Exposing FP4+ at ASA 125 is guaranteed to give me no detail whatsoever in the shadows.<br>

And I don't think that's me or my equipment. I used the same camera, the same exposure meter and the same technique in all cases. Besides, I can swear by my lightmeter's accuracy. I never had an under- or overexposed slide in over five years of using this meter, not even by half a stop.