Archived posting to the Leica Users Group, 2005/11/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 2:55 PM -0800 11/22/05, Adam Bridge wrote: >So I've gotten this general impression that a substantial number of >folks aren't fans of stop baths for black and white negative film and >just slosh around water in its place which. > >So what's the thinking here? The stop bath gets in the way of fixing >later? Has some bad effect on film grain? I would assume that it would >be a good thing to quickly stop the development process. > >Now when using very dilute devopers, like XTOL 1:3 where it's >essentially completely expired at the end of development, I can see >that just washing the film for 30 seconds with water might not be a >bad thing. But what about 1:1? Or some other developers? The main problem is that pinholes can develop. If you do use any 'stop bath', dilute it a lot. I'm not in a real hurry to get the negs done, so try to have my development times in the 10min. plus range so that pouring times/effects don't interfere. When you do that, and do it consistently, the additional development that occurs during the water bath is easily dealt with as you test your procedure. Then again, if you are a volume user and develop 6 or more rolls at a time in a tank, you shouldn't use very short development times as then you will get streaking due to some portions of the film getting a lot more developer time as a percentage than the rest. For evenness and general quality I use a presoak, and then develop HP5+ in Xtol 1:3 with decreasing agitation, letting it stand for 5 minutes at the end for a total time in the developer of 17min. at 21?C. All this with 7 rolls of 36 in a SS Nikor tank intended for 8, with the 1:3 developer going to the top. Then a water bath, etc. Delta 100 gets treated similarly, but for less time. I get an effective speed of 200 for the Delta 100, and 64 to 800 for the HP5+. Tri-X gets me 400 using a similar technique. Xtol seems fairly sensitive to water quality, and this will also affect your times. I use local tap water, but both hot and cold are filter with a particle filter, and the mixed water is again filtered through charcoal. I had this setup long before Xtol came out, and it works fine and gives me peace of mind. The developer is essentially exhausted as you indicated, and only the shadow areas get some development in the last 5 minutes. That's why I get an effective speed increase. All this said, I haven't used stop bath since the 60's, when I did have some problems with pinholes and stopped using it. That was in a different place, with different water and D-76. That water wasn't filtered, or certainly not as well, and particulates in the water in combination with stop bath can cause further problems. -- * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com