Selection of Sources of Infrared Radiation for Drying Processed Motion-Picture Films
Forced methods of drying processed motion-picture films take advantage of the principles of convective heat transfer and radiative heat transfer. Although in principle an infrared radiation source is good for this purpose because it can concentrate heat below the surface of the film, in the past there have been difficulties because different film densities absorb radiation differently, which leads to uneven drying and distortion of the film. An optimum infrared source would have a radiation spectrum corresponding closely with the film's absorption spectrum and during drying would maintain an equilibrium of moisture content between the emulsion and the base. Source-emittance and film-absorption characteristics were examined with an IKS-14 infrared spectrophotometer operating in the double-beam mode from 0.75 to 15 μm, A wavelength band was found in which variation in image density has little effect on the absorption of infrared radiation. A tubular metal emitter at a temperature of about 480 K (about 405 °F) is found to be nearly optimum.
- Print ISSN
- 0361-4573
- Published
- 1974-10
- Content type
- Original Research
- DOI
- 10.5594/J13435