Archived posting to the Leica Users Group, 2000/07/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 10:53 PM 7/25/00 +0100, you wrote: >> I had long understood that underexposing and overdeveloping increases >> contrast. And somewhere, somehow (I can't recall and can't explain >> it), I had gotten the impression that, conversely, overexposing and >> underdeveloping rather decreases contrast. > > As I recall, overdeveloping will >also increase grain size. Look at it from the other direction.... Less development causes the curve shape to flatten out. If your speed point, say an exposure for Zone I, was at .10 DU above fb&f it's now _lower_ than .10 DU, therefore if you want to maintain a speedpoint of .10 DU you'll have to give the film more exposure. Conversely, more development increases the slope of the curve; your speedpoint is now denser, so in order to get the desired .10 DU for Zone I you'll need to give less exposure. Giving more exposure while not decreasing development moves the deepest shadows up off the low-contrast toe area of the curve into the low end of the straight-line middle section, or iow increases shadow contrast. With old films it could push the highlights up into a low-contrast shoulder area, making them look muddy, but that's just about impossible with modern films. Other things being equal, increased development increases apparent graininess. John Hicks jbh@magicnet.net