Development of films designed for a normal pictorial characteristic curve, should begin with the manufacturer's recommendation. Most microfilms do not fall in that category and require modified development schemes to achieve the full grayscale associated with pictorial photography. Although I have had excellent results with Kodak's recommended Technidol developers for Tech Pan, I have found Rodinal with sodium sulfite provides me with more control and much shorter development times. Since Rodinal is a reasonably active developer and will produce VERY contrasty results with normal development, higher than normal dilutions and limited agitation, are needed to produce a normal contrast index.
The traditional spiral developing tank in which developer flows through narrow passages between layers of film creates serious problems for high energy developers when limited agitation and/or high dilution is used to control contrast. Special care is required with the agitation pattern, especially with 35mm film to avoid streaks from developer swirling through the sprocket holes. Several solutions have been proposed for a 35mm developing tank. The simplest, the "golf tube", proposed a number of years ago by an author to whom I wish I could give credit, is inexpensive and works quite well. The only disadvantage of the "golf tube" is the need to work in the dark because of the absence of a light trap.
Kodak is quite specific in their directions about the agitation method to be used with Technidol - different for the solid version than for the liquid. Both involve carefully lowering the loaded reel into the developer rather than pouring the developer into the loaded tank.
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A 35mm technique which has, for me, provided the best results with the traditional spiral tank, was suggested by Bill Hoy of Bedford County, VA.
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The developer volume I use results from noticing that Minox rolls developed in a 250cc tank looked much better than 35mm rolls developed in the same tank. I concluded that the actual amount of developing agent was a factor in the degree of reduction of silver halides. Negatives developed with too much developer, regardless of dilution seemed to have a better tonal distribution. I chose as a minimum, the amount of developer in a 1:25 dilution in a 250cc tank, for a 36 exposure 35mm roll of film. Thus, for such a roll, 10 cc of Rodinal concentrate should be present in the tank, regardless of dilution. A Minox roll, with approximately 1/10 the exposed area, would require 1cc. In practice, I use less (6.5cc) for 35mm and more (2.5cc) for Minox. The Minox negatives still look better! Remember that these are MY results, with MY equipment, and MY procedures, AND MY EXPECTATIONS. Your results WILL be different.
I generally develop film with either Rodinal or PMK Pyro, each of which produces negatives expressively and physically different from the other. So, with the variables of scene luminance and film selection, as well as choices of developer, dilution, and development time, the possibilities are endless - and that's what makes it FUN!
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The chart and table are the ones I am currently using. For PMK Pyro, I use the agitation scheme recommended by Gordon Hutchings, with only a single invert for Tech Pan and Super HR Agitation for 1:50 Rodinal follows Agfa's directions on the Rodinal package. The addition of infrared film to the mix resulted in the inclusion of XTOL and the time and agitation scheme from the Kodak website. When exposing according to the "f/16 Rule" using ASA 60 and the Rollei red filter, this time and agitation are excellent for me.
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