Photographic developers modifiers

C15-0129. Photographers use a rule of thumb, that a 10° C rise in temperature cuts development time in half, to determine how to modify film development time as the temperature varies, (a) Calculate the activation energy for the chemistry of film developing, assuming that normal temperature is 20 °C. (b) If a certain film takes 10 minutes to develop at 20 °C, how long will it take at 25 °C ... 

The major features for advanced photo-systems relative to the base film are a small-size thrust cartridge and return inside the cartridge. These features require low core-set curl values and high mechanical strength. The cellulose triacetate (CTA), polycarbonate and PET materials currently used in the photographic industry are not able to satisfy these requirements. Some newly developed film materials, such as modified-PET and syndiotactic polystyrene, were also unable to satisfy such requirements. It is known that annealing films just below the Tg (BTA treatment) could reduce core-set curl tendencies. BTA treatments of... 

In a number of cases, radiation has been applied to the precursor of a catalyst before the final step of preparation, with the hope of modifying the course of that step to produce a catalyst of higher activity or altered specificity. A general model for such an effect can be seen in the photographic process, in which a latent image produced by light is affected differently by the subsequent development step than is the nonilluminated part of the emulsion. 

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