Response to agitation: I do it different; it works, so why is it the oddball way?

Hi Shawn, Back in my roll-film back days I shot lots of 120 film and developed it in Nikkor steel tanks using the "famous" torus method. This gave me uneven development occaisionally (higher-density stripes along the long edges of the film), so I dedicated a day to experimenting with agitation techniques. I exposed roll after roll of film under the enlarger, loaded them on reels, developed them using different types of agitation, inspected them after a minute in the fix, and threw them away. In the end I determined that my problem was from a combination of filling the tank too full and under-agitation, but I also found that a lot of different agitation techniques work just fine. I now (for the rare occasions when I develop roll film) use the "martini shaker" technique, shaking and turning the tank really vigorously 5 seconds every half-minute after a 30 second intial agitation, but I've used the up-and-down only method and the rotary twisting method successfully as well (I had one tank with a leaky lid which I never inverted). The main thing is to do the same thing consistently so your results don't vary. Agitation technique can have an effect on development time (more vigorous agitation shortens the time and vice-versa). Long development times with dilute developer and only occasional agitation (once every few minutes) can be used for a compensating effect for N- negs since the developer becomes exhausted in the high-density areas but continues working in the low- density areas for some time. Again, consistency is important. As far as teaching goes, what's stopping you? Just show the students what you do, tell them what others do and let them find their own personal "style". The main thing is to make them aware of the defects possible from inadequate agitation and to be able to help them when they have problems. Regards, ;^D)

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