Thank you, Mr. Robb. This one gets saved and printed. One of these days I may try processing my own C-41 stuff. Until then, I'm a mini-lab kind of guy who loves to curse the dust and scratches they tend to create.
William Robb wrote:
----- Original Message ----- From: "Lon Williamson"
Subject: Re: bad experience with Kodak lab
What are the problems that can happen with dip and dunk? I've not heard of any from a good lab, but then I've never tried this more expensive method.
In a dip and dunk process, the film is suspended on a hanger, and a weight is attached to the bottom. The hanger is put onto a suspension which moves the hanger up and then down into the first tank. The process continues, with the hanger being lifted, moved forwards and lowered into the rest of the processing tanks. It is possible for a clip to let go and drop the film, or for a weight to let go, and allow the film to float, though neither is likely. Agitation in D&D processors is via nitrogen burst. Nitrogen is released from a tank and directed to the bottom of the tank where it rises to the surface. This agitates the chemistry. Nitrogen bubbles can cling to the emulsion and cause underdevelopment, in much the same way that air bells cause underdevelopment in small tank processing. Fuji RVP is particularly susceptible to this, but all Fuji films are prone to it. As the film is lifted from the tank, chemistry flows from top to bottom, and flow marks can result from this action. D&D processed films are often slightly overdeveloped on the low end, as the film is dropped quickly into the developer, but raised somewhat slower, and is suspended over the tank to drain for several seconds. Finally, since there is no squeegee action for removing surface chemistry, D&D processed films are prone to uneven drying, and can exhibit amoeba like flaws in the emulsion from droplets of final rinse draining down onto partially or completely dry emulsion.
In my own limited experience, I think that rotary tank processing is the safest, and most even method of film developing, followed by a well maintained ciné processor, then dip and dunk and properly maintained leader transport processors. The worst method, in my opinion, is roller transport processing. HTH
William Robb
