Abstract

A method of ascertaining the gradient speed of a photographic material without the use of special gradient measuring instruments is pointed out. The derived formula shows the relation which must exist between density and log exposure at the value of exposure which is the reciprocal of the speed.

© 1941 Optical Society of America

Comparison of Graininess and Speeds of Different Types of Photographic Films

C. E. Barthel
J. Opt. Soc. Am. 31(8) 513-520 (1941)

Methods and Instruments for the Determination of Photographic Speeds by Measurement of Relative Characteristic Gradients*

Clifton Tuttle
J. Opt. Soc. Am. 29(7) 267-277 (1939)

Minimum Useful Gradient as a Criterion of Photographic Speed*

Loyd A. Jones and M. E. Russell
J. Opt. Soc. Am. 25(12) 396-411 (1935)

Number of Quanta Required to Form the Photographic Latent Image as Determined from Mathematical Analysis of the H and D Curve. Part II*

J. H. Webb
J. Opt. Soc. Am. 31(9) 559-569 (1941)

The Brightness Scale of Exterior Scenes and the Computation of Correct Photographic Exposure*

Loyd A. Jones and H. R. Condit
J. Opt. Soc. Am. 31(11) 651-678 (1941)