Another way of stating this is, "box speed" is by definition a minimum
exposure. It's usually phrased something like "the minimum exposure
required to get a printable negative on no. 2 paper" or something to
that effect.
For a film of any given amount of exposure latitude, exposing at the
published speed leaves no latitude toward underexposure, and all of the
latitude toward overexposure.
David Foy
Cor
The statement below is incorrect, and has been proven wrong so many times. Film is very sensitive to underexposure. Lost shadow detail cannot be retrieved with increased development. On the other hand, film is also very insensitive to overexposure. I tested film with up to 10 stop overexposure and still made excellent prints. However, printing at box speed is significantly inferior to exposing at half that speed. Exposing at box speed is a compromise, making many assumptions, and might be acceptable for some types of photography (sport, street or journalism), but if maximum print quality is required, box speed won't get you there. Rule of thumb is box speed / 2, or at least 2/3 stop less than box speed.
Next time you expose film, make the test and expose a few frames with 1, 2 and 4 stops overexposure. You won't believe the shadow detail!
Regards
Ralph W. Lambrecht
http://www.darkroomagic.com
On 2006-04-12 09:13, "Breukel, C. (HKG)" <C.Breukel@xxxxxxx> wrote:
-----Original Message----- From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver- bounce@xxxxxxxxxxxxx] On Behalf Of Ryuji Suzuki
The part that affects contrast is development time and temperature. With negative emulsions, exposure error within one stop is unimportant because negatives are developed to such a low contrast and the image contrast is boosted at the time of printing. Therefore it is perfectly acceptable to shoot at the box speed, or maybe half the box speed, and adjust the development time to print well on grade 2 paper.
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