Exposure techniques

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I will be going to Cambodia to photograph some old temples. My concern is about the low range of light (probably 2 or 2 1/2)on some of the carvings on the temple walls. The walls are mostly unicolored with various greys and tinged with a light green. There will be shadows from the relief carvings itself. I will be using TMax and will develope with N+1 or N+2. Would any filters be useful? I'll listen to any other suggestions. Thank you.

-- Cal Eng (caleng@inficad.com), April 12, 2001


Filters might provide limited local contrast options in b&w given your description. The shadows are likely to be bluish while the parts in sun would be grey or green. Something like a minus blue or yellow filter might help a bit but not much. I take it you don't want to mess with lighting. It might be a good idea to take some document film along - something like Tech Pan. Also, have you considered developing in something like pyro? Most of the density can come from stain and you might be able to avoid the grain etc from overdevelopment. Good luck. DJ.

-- N Dhananjay (ndhanu@umich.edu), April 12, 2001.

Hi Cal, you might want to look at that book Quite Light as most of the shots are in low light, and I think there is little piece on how each was taken in the back of the book. Oddly enough, shooting in the desert had some interesting low contrast situations even though the sun was blasting. Later I noticed others who were doing what I was trying to do had been using filters all along. After going through a lot of film, I finally came around to filters to enhance contrast. Assuming you can pick your time a day for high-lighting, using filters might do it. I remember National Geographic did a piece on those old temples not too long ago, perhaps you can find the photographers who did that piece and ask what they encountered and what they recommend. Good Luck. David

-- david clark (doclark@yorku.ca), April 12, 2001.

Check out this on-line article on photographic techniques for photographing petroglyphs: htt p://ourworld.compuserve.com/homepages/jrmartin/photo.htm

-- Ed Buffaloe (edb@unblinkingeye.com), April 13, 2001.


One easy way to increase contrast without overdeveloping is to take advantage of the reciprocity failure effect. I have found that contrast increases approximately 10% with each doubling of the meter indicated exposure time. For example, if your meter calls for 15 seconds and the reciprocity correction for that film is one minute, that equals 2 doublings (15x2x2=60 seconds) and would be equal to about 20% more development. With long exposure times and neutral density filters, you can use this to your advantage. I particularly like the look of negatives expanded in this way. Although I have done no curve plotting, I believe that the curve shape is different for these negatives that for negatives expanded by extending development. This works for the films I use. (Tri-X, T-max 100 and BPF 200)

I have also found that strong filters affect the contrast of some films. This you might use to your advantage as well. Tri-X, in my experience, gains about a Zone of contrast with a number 25 red filter. This effect is so pronounced that I figure it in when determining development. T-Max, on the other hand, loses contrast with the 25. You might do some experiments on low contrast subjects with some filters and see for yourself. Also, a combination of the two effects should be additive. Therefore, Tri-X with a 25 filter and a long exposure should give you lots of added contrast. As I said, you have to test for yourself, but these techniques keep the grain down a bit and are quite flexible.

Hope this helps, ;^D)

-- Doremus Scudder (ScudderLandreth@compuserve.com), April 13, 2001.

I just visited the web site suggested above by Ed and found that advice to be good as well. I use my dark cloth (which is white on one side) for a reflector often. Regards, ;^D)

-- Doremus Scudder (ScudderLandreth@compuserve.com), April 13, 2001.

Cal, I would do a bit of experimenting before you go. It should not be that difficult to find a similar lighting and texture somewhere near home. Get out the old polaroid back and shoot the subject with various filters. If you bring the back with you to Cambodia you can do the test right there. If I had to guess, I would guess a green filter. It seems whenever I am looking for texture and contrast in wood or rock, that is the one that gets me what I want, but everyone has different tastes. Have fun and a great adventure on your trip.

-- Paul Mongillo (pmongillo@thurston.com), April 13, 2001.

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