Black and white film exposure

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I have been shooting color slide film for about a year now and my exposures are usually dead on. I recently tried black and white film(TMAX-100) and my shots came out underexposed. I was shooting into a small waterfall with the sun shining off the water. I metered off the brightest part of the scene and added 2 2/3 stops to get to medium gray. Can anyone help me with the basics of exposure for black and white film, film latitude, etc?

Paul

-- Paul Calvert (opie@roava.net), February 23, 2001

Answers

no. but one thing that dont help is the fact of all color films gives more saturateds colors that nature by default, because people likes that way. and its normal to see people adding 1/2 stop always, just to saturate a little more. come on, things are not like on national geographic.

-- celcio cobani (d0nk@softhome.net), February 24, 2001.

Paul, are you developing your own b&w, and have you been doing it for a while, or are you sending it out to a lab?

chris

-- Christian Harkness (chris.harkness@eudoramail.com), February 24, 2001.


Paul: There are a number of variables that could have resulted in underexposure. Which film developer was used and at what dilution? With this developer and dilution, is there a film speed loss? If it was processed by a lab, do they use a replenished system? If so, does this result in a film speed loss, and do they keep it correctly replenished? These are just a few of the variables that might effect the final speed rating you use.

Basing your exposure on the highlights of a scene can be a safe thing to do with slides since the highlights are the thinnest areas of the slide. These thinnest areas have the least lattitude for overexposure, so they need to be handled most accurately. But with negatives, it's the other way around. The shadow areas are the thinnest area of the negative and are the most critical. They have the least lattitude for underexposure, so it is usually best to base the exposure of negative film on these shadows. That is why when using the Zone System, exposure is based on the darker shadow areas that should still show some shadow detail.

You probably would have been more successful if you had metered the shadows and then stopped down a stop or two or three (thereby placing them in the appropriate Zone). It is a little difficult to say exactly how many stops would be required without being able to meter the scene myself. If you are using 35mm, then by all means bracket. If you are working in larger formats where the film is more expensive and processing becomes quite time consuming, I would recommend that you read a few of the books that discuss the Zone System.

-- Ken Burns (kenburns@twave.net), February 24, 2001.


Paul

When you say underexposed, please tell us what the negatives looked like. Also, let me start you in the correct direction. As I have said in these forums many times before, just becasue a film, shutter speed, f stop, meter, paper, developer, says something doesn't mean it is so. Everything affects everything. YOU NEED TO TEST. The best test I know of is to find your working ISO. That is done by finding the ISO that, when you expose for zone 1 gives you a density of between .8 and .12 above film base plus fog. Once you find that, and learn how your meter works, you will more than likely alwasy get enough exposure. The next step would then be to control contrast by determining the proper development time. Generally, for a condenser enlarger that would mean a zone 8 density of about 1.25 and for a noncondenser enlarger just a little bit less. (that is for a normal number 2 paper of course). You will need to read a few books a few times to really understand what I have just said. And then of course have some means of controlling your processing. I can highly recommend Ansel Adams series, as well as a small book called Zone VI workshop by Freed Picker, and the Beyond Basic Photography book by Henry Horenstein. All of the mumble jumble about exposure and development is not going to come to you over night. It might take awhile and some experimenting to understand. Take you time and don't become frustrated. Eventually you will be just standing there and it will pop into place, you will say YES, and that will be it. So don't get discouraged. Read the books first. then come back with your questions. Kevin

-- (kjkolosky@kjkolosky.com), February 24, 2001.


Sorry about all of the misspellings above. kevin

-- Kevin Kolosky (kjkolosky@kjkolosky.com), February 24, 2001.


If you successfully shoot slide film, B&W exposure should be easy. TMX has way more latitude than your slide film (though it's not my favorite choice). There are certainly other metering methods that might be better, but if your method would have given you a good slide, it would likely give you a good B&W neg. Are we talking a lot of underexposure here? Did you process yourself or use a lab? Are there any other shots on the roll that don't have unusual metering problems, i.e., just normal front lit subjects, that could be used to separate an exposure problem from a processing problem? Does the film leader have good density? That can be a clue about underdevelopment, albeit not a very scientific one. More questions than answers, but that's the first step!

-- Conrad Hoffman (choffman@rpa.net), February 24, 2001.

Paul, a correctly exposed T-MAX negative often appears thin in comparison to other emulsions. You might try Tri-X, or, since you are using ISO 100, Plus-X, Ilford Delta Pro 100, etc. Also, the shot you are basing your conclusions on was a very tricky shot. How about shooting an average subject in direct sunlight, at 1/250 at f/8 1/2, as a better test?

Regards,

-- Bob Fleischman (RFXMAIL@prodigy.net), February 25, 2001.


"Expose for the shadows and develop for the highlights." About half the way through your development time (black and white film) is the full deal. The rest of the time is all density build up (highlights). What if you meter a deep shadow and expose it for zone 2 but you cant figure out how to put your brightest highlight back on the scale. Just under develop, but not by more then 50% of your development time. I also recommend any Henry Horenstien book. And if you listen to any Black Sabbath record backwards you might find tips on the zone system.

-- Mark (marktt@nac.net), October 25, 2001.

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