Archived posting to the Leica Users Group, 2001/12/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]My belief is that with current films and developers, there is no significant difference between sufficient agitation and extra agitation. Correct agitation was of importance perhaps thirty years ago, when films were grainier and the fine grain film/developer combinations were of low contrast. There was a flurry of the use of so-called "acutance" developers that would produce Mackie lines. On the negative, between a heavily exposed and moderately exposed area would be a fine light line. On the print, this would become a dark line and, if subtle enough, would not be noticed but would give the illusion of greater resolution. The light line was produced by local exhaustion of the developing agent. The effect was critically dependent on just the right amount of agitation. Too much, and the effect would disappear. Neofin Blue was the developer I played with around 1970 something. I also made up a home brew "Beutler" developer--I think it was just metol and sodium carbonate. With the home brew stuff, the Mackie lines were so strong the the results were interesting but not very appealing. I read that the commercial developers, such as Neofin Blue had proprietary trace ingredients that toned down the effect. Years later, I bought some Neofin Blue out out of curiousity. The instructions for agitation were entirely different--possibly the formula was also different. It was apparent that it was no longer being promoted as an acutance developer. Herb - -- Herbert Kanner kanner@acm.org 650-326-8204 - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html