Latent image considerations

The photographic attributes of (S+Au)-sensitization are similar to those of S-sensitization. Both act primarily to increase the sensitivity for surface image formation. Both usually decrease the sensitivity for internal latent image formation in emulsions that show considerable internal sensitivity in their unsensitized form. Bahnmueller (163) and Farnell and Solman (164) observed that, in emulsions of this type, the combined (S+ Au)-sensitization produced a greater increase in surface sensitivity and a greater decrease in internal sensitivity than S-sensitization alone, but sensitization with gold alone increased surface sensitivity without impairing the internal sensitivity (163). 

Latent image fonnation involves the creation of free electron-hole pairs by the absorption of an image exposure and the displacement of these carriers by a field. Experimental techniques for characterizing these phenomena are of considerable importance to xerography. This section reviews experimental methods for measuring parameters that describe charge generation and transport phenomena. 

The development process converts the latent image in the polymer into the final 3-D relief image. This process is perhaps the most complex of resist technology. It can generally be achieved by either liquid development or dry (plasma) development. Numerous considerations are critical to either alternative. We will first focus on the wet development process. Plasma development will be discussed in a later section. 

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