Latensification

Latensification can be brought about in several ways. One in which the effect must be ascribed to an increase in size of the sub-image nuclei makes use of a secondary exposure to light of low intensity. A second method in which the effect most probably is brought about by an increase... 

Fig. 7. Effect of gold latensification on the rate of development of a motion picture positive film. —x—x—, Intensified film —o—o—, untreated film. Curves are plotted for several values of log E, where E is the energy of the light exposure.

A technique of post-fogging called latensification (Ref 2a) can frequently increase the maximum recording rate up to four times. 

With old-style emulsions, such as Efke 25, 50, and 100, it was possible to use methods found in the 2nd edition of the Cookbook, such as the Hydrogen Peroxide Pushing Method or Acetic Acid Intensification, to create a true increase in film speed. Unfortunately, modern emulsions, whether they are conventional or flat-grained, rely on color dye sensitization to achieve their sensitivity as much as upon silver sensitivity. Color dyes do not respond to these speed increasing techniques. Hydrogen peroxide will do little or nothing and acetic acid latensification may ruin your film. I no longer recommend either. 

The best point of attack for a determination of the surface electrochemical properties of latent images is at the level of latent sub-images. There can hardly be more than three sizes (2, 3,4) without gold sensitization, and only one size (N=2) with gold. Indeed, the continued presence of optical latensification effects after the application of optimal gold sensitization established the development threshold at N=3, not 2, in the presence of gold atoms. 

The return of optical latensification in the range from -170 to -210mv indicates that there is a less stable LSI which is being destroyed completely at potentials less negative than -170mv. 

Figure 21. A family of experiments, of the silver density difference produced by treating film samples paralleling Figure 20 with optical latensification after latent image degradation by one of several buffer solutions.

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