Superposition or mixture of simple quantic characteristic curves of photographic emulsion layers. The corresponding relative contrast

✍ Scribed by L. Silberstein

• Publisher: Elsevier Science
• Year: 1951
• Tongue: English
• Weight: 645 KB
• Volume: 252
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(51)91052-6

✦ Synopsis

The need of a superposition of two (or more) simple quantic expressions for the photographic density as function of exposure has originally arisen through the necessity of reducing the quotient y/Dr. (relative contrast) below the lowest theoretical value of the relative contrast which belongs to an exponential emulsion, under the one-quantic hypothesis, 2 namely, ~//Dr" = 0.682. Now, experimentally, much lower relative contrasts have been measured for a great variety of emulsions, not only the commercial but also the experimental ones, as will be seen later on.