A method and apparatus for depositing a layer of processing fluid on an exposed film strip contained with the processing fluid and fluid depositing means in a multipurpose film cassette of the type in which the film strip is exposed, processed and viewed by projection without removal from the cassette. The processing fluid is doctored onto the emulsion side of the exposed film strip during rewinding movement of the strip under an applicator nozzle opening. The film strip is supported under a biasing force toward the nozzle approximating in magnitude the hydrodynamic force developed by doctoring the processing fluid against the other side of the film strip thus to achieve a net balance of forces on opposite sides of the film strip so that foreign particles such as dust and the like will pass the doctoring surface without deleterious accumulation of such particles thereon.