Water Marks in Developing

If water gets on a film before it is developed, that part of the emulsion will swell more and the development rate will differ, leading to an ugly mark in the image.

Some processes (e.g. C41 and E6) call for a pre-wash of a few minutes, in which case any drips are irrelevant because the entire emulsion is wet before the developer reaches it. For other films, it is critical to dry the inside of the processing tank (and all funnels leading to it) before loading film.

Example image:

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