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Abstract
The covering powers of a wide variety of photographic silver deposits have been measured to discover the requirements for maximum covering power, for convenience, results for deposits produced by chemical development on the one hand and by physical development on the other and the inter-comparison of data are presented in three separate parts. This first part refers to chemical development.
Relationships between covering power in the region of saturation density, CPS, and the size of the undeveloped grains, are presented for chemically developed emulsions representing the whole grain-size range occupied by commercial materials. In general, CPS is independent of mean grain area where this is between 0.002 and 0.05pm - and inversely proportional to its square root for larger sizes. Experimental data are analysed with the aid of an expression derived from the Nutting formula for density to separate the effects of grain size, grain size spread and grain shape. Factors affecting covering power at saturation and lower densities are discussed.
Notes
Paper presented at a symposium on “Factors Limiting Photographic Performance” Organized by The Royal Photographic Society on 11-13 December 1968 in London.