I have seen a few threads that mention same film exposure lattitude especially in regard to BW and street photography. I knew about pushing/pulling and entire film although I have never done it, but could someone please explain this. Is it only viable if you print yourself? What films lend themselves to this- BW and C 41 color? Thanks, Silas

-- Silas Larsen (slarsen@mail.colgate.edu), October 29, 2001

Answers

All films have some degree of exposure latitude. How much is somewhat subjective, but certain characteristics are easy. A lot of it has to do with how poor a negative you can use to make an acceptable print. Of course, the best prints are always made from properly exposed negatives...

Color transparency: Latitude is on the underexposure side, -1 to +.3 EV
Color and BW negative (C41 process): Latitude is for overexposure, -2 to +5EV
Standard BW negative (silver image process): Latitude is quite variable, depending upon developer and processing technique, but is biased on the overexposure side, usually -1.5 to +3 EV is what I find.

Remember that film speed is partially a measurable attribute of a film and partially a subjective thing. Making negatives that produce satisfactory prints of whatever description is all that really matters.

-- Godfrey (ramarren@bayarea.net), October 29, 2001.

Films only have latitude to the extent that the available range of densities in the film exceeds the contrast range of the subject. If the subject has a five-stop luminance range, and the film has five stops worth of density changes, then there's only one correct exposure, and thus no latitude at all.

How's that for being a know-it-all? An old book--I think it must have been by Aaron Suskind--had a better way of putting it. If a six- foot man chacks into a hotel that has a six-foot bed, then he fits, but there's no latitude. If a five-foot man chacks in, there's one foot (+/- six inches) latitude. If a seven-foot man checks in, he must lose either head room or toe room, i.e., over- or under-exposure.

-- Bob Fleischman (RFXMAIL@prodigy.net), October 30, 2001.