What mean N-2greenspun.com : LUSENET : B&W Photo: Alternative Process : One Thread
When I read this line: ...the exposure by one stop under, and developping to n-2...., What is the sigification of N-2 ?
-- Michel Berard (email@example.com), June 05, 2002
It's Zone System shorthand. "N" refers to your "Normal" development time, whatever that may be. "N-1" would mean a decreased development time to reduce negative contrast, essentially by one paper grade. Often used with camera exposure increased by one stop, to retain density on the neg. The different time is found by testing. "N-2" is the next step, decreasing development by 2 paper grades. "N-2" is fairly radical for modern films and would suggest a subject of extreme contrast. The more common "pushing film" goes the other way, decreasing camera exposure and increasing development, which raises negative contrast. This is known as "N+1" or "N+whatever". A good Zone System manual (Adams) will explain better.
-- Mark Sampson (MSampson45@aol.com), June 06, 2002.
N-2 is equivalent to a decrease in normal development time by a factor that will cause an associated decrease in negative gamma or the slope of the film's contrast index. Contrast can also be associated with paper grade (obviously) but negative development times related to the zone system refer to negative contrast. N-2 (with proper exposure) will produce flatter negatives. It is usually used with high contrast scenes where the contrast range will most likely exceed the usable range of densities in a normally developed negative. N-2 when used with increased exposure will allow development of shadow detail while preventing excessive highlight density.
N-2 development is really pushing it with todays thin emulsion films, and tends not to be as successful as it was with the films common in the 30's and 40's. On the other hand, todays emulsions have improved considerably in their ability to manage contrast with proper normal development, and with the advent of Poly papers and split printing techniques, N-2 development is not used nearly as often as it used to be.
-- don Sigl (firstname.lastname@example.org), June 06, 2002.