Film Speed Test : LUSENET : B&W Photo - Film & Processing : One Thread


I am currently reading Ansel Adam's, The Negative. I am trying to perform his film speed test. (Appendix A, pp 239 - 240)

The test requires that we shoot the first exposure on Zone I at the film manufacturer's ASA speed. We are to set the expsosure meter to the manufacturer's speed and then set the camera so that the exposure is on zone I. For example, I am using Ilford 400 and I set the meter to 400 and take an exposure setting that is equivalent to zone I.

Then on subsequent exposures we are to change the ISO setting in increments of 1/3. AM I SUPPOSE to change the exposure settings on the camera in order to obtain zone I for each different film speed I use. Or, I am only supposed to change the film speed and leave leave the exposure settings that gave me zone I at the manufacturer's speed.

Thanks, David

-- David Sinai (, September 04, 2001


You can:

1. Open up (stop down) the lens 1/3 stop from the 400 speed to represent 1/3 stop slower (faster) film, i.e., 320 (500).


2. Change the film speed on the meter and re-read. If light hasn't changed, you should get the same net exposure. If you don't your meter isn't linear, and needs fixing or replacing.

-- Charlie Strack (, September 04, 2001.

David: The film speed test is only the beginning if you want to be rigorous. You need personal developing time and contrast evaluation. Also. it is really valid only for sheet film, as it is more difficult to control +/- development, which by the way is almost needless now that good MC papers are availble.

All this work was done when the only paper was a grade 2 and all negs had to be tailored to print on that paper.

Try getting a copy of Fred Picker's "Zone VI Workshop", as it has all the detailed instructions along with smple of everything. He is a bit quirky IMHO but he is technically correct with all the sensitometry stuff.


-- RICHARD ILOMAKI (, September 04, 2001.

another option: set your camera to the recommended ISO. bracket each shot for the next several rolls of film. evaluate the low values for the best detail you are looking for. more than likely it will be the initial meter reading or one stop more exposure. once you have determined this, set the ISO and leave it. Shoot an entire roll of film of a single full scale subject and develope 1/3 of the film at the recommended time/temp; 1/3 at 10% less time; and 20% less time. make test prints that show the best detail in the high values and maintain good detail in the low values. this will give you the best development time for your film/camera. it works well enough for roll film and the wide range of exposures you might be taking on a single roll of film.

-- r (, September 05, 2001.

Don't bother with the tests. Ask yourself two simple questions.

One: have your negs of everyday subjects got enough shadow detail? If not, with each subsequent film lower the film speed by 1/3 stop, i.e. 400-320-250-200-160 until the whole film is more or less to your satisfaction.

Two: do they print on your favoured grade of paper? If you regularly need soft grades, cut development time by 30 sec for each film until they do. If you regularly need hard grades, increase development times by 30 sec for each film until they do.

The Zone System has hindered more photographers than it has ever helped. If you understand enough sensitometry to take full advantage of it, you don't need it, and if you don't understand enough sensitometry to take full advantage of it, you'll only confuse yourself.

-- roger hicks (, September 26, 2001.

I adamntly disagree with Roger but first let me answer your question. Once you have changed the ASA you will get a new combination of shutter speed and aperture for a Zone I exposure, use the new setting. Practically what you are doing is taking diferent exposures by 1/3 around the manufacturers recomended film speed. For example if your inital exposure is for ASA 400 and then you reset the ASA to 320 then what you actually did is overexpose by 1/3 stop.

As to Roger's comment I could not disagree more, sensitometry is only a TOOL of the zone system, and not a dificult tool to use at that. It might have confused him, but do not let him discourage you in using a tool that will allow you to diagnose a problem in the future if your film is not comming out as you want it, it will allow you to compare different films and different kinds of proccesses with the same film, etc. Beleive me the time you are spending now learning sensitometry will save you a lot more time and effort in the future.

The zone system will allow you to be confident in your choices of tonality, it will allow you to determine your mistakes in exposure and it will allow you to determine the limits of your film/developing combination. In the end the zone system is also a TOOL and like every tool some people are better at using it than others.

The only one thing I will mention about the zone system is that like every new tool you tend to overuse it at first, and spend a lot of time doing tests and not taking pictures, don't fall into this trap, I did and realized that I was testing for every film under the sun in search of the "perfect" film/developer combination. There is not such thing and here is the beauty of the zone system, it will tell you what the limits are and what films would be better used under different circumstances. WHy do you think that many LF photgraphers use more than one film? It has to do with aesthetic choice and knowledge of the film, some gained through empirical experience and a lot of money wasted, I imagine this is the case with Roger, and in most cases with experienced gained by doing tests and understanding how a film behaves.

You have the AA book, in my opinion it is the best, it is simple, it tells you what you need to do and it moves on into the real meat of photography which is making informed choices about the tonality of an image you wish to record. If you use Roger's recommendation and develop a little more here expose a little less there what you will end up is a method in which you will not be able to determine why things went wrong, and when they do work your print will probably look all the same, as I suspect his do. Good luck, and stick with it, trust me on this is time well spent.

-- Jorge Gasteazoro (, September 27, 2001.

Having known a good many professional photographers and a lot of amateurs, You learn your materials thoroghly by testing or you guess and never get better or only slowly. Test your film. If you are happy with snapshots, fine. But if you want to nail every shot then test. The zone system is only, and I say "only" a tool which gives you the knowlege to know what your materials can do in a given lighting situation. Don't think paper grades alone can make a good print. If you expose you film to little then you won't have any shadow detail. Just blank blacks. If you give it too much exposure you will get flat prints no matter what paper grade you use. And lots of grain. The tests are easy and once you do them and understand what they are telling you, then you can shoot with confidence every time. That goes for color film too. You've nothing to lose and everything to gain. Why waste materials and images? james

-- james (, September 29, 2001.

And Adam's books in their later editions were all written with the new VC papers in mind. When he wrote about a grade 2 paper he was referring to both a graded paper and/or a VC paper at an equivelant grade 2 filter. James

-- james (, September 29, 2001.

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