Sensitometric comparison of dental films of groups D and E

In early 1981 Kodak introduced into the market Ektaspeed dental film of speed group E, which is more sensitive than Ultra-Speed film of speed group D. This investigation compared the sensitometric properties of Kodak dental films of speed groups D and E. By plotting a graph of density against log relative exposure, the characteristic curves were drawn for the two types of films. The curves showed that film E was approximately twice as fast as film D. A table derived from a mathematical description of the characteristic curves permitted the formulation of exact exposure-multiplying factors for changing from one type of film to another. Both films had almost the same useful density range, but film D had higher average film contrast and lower latitude than film E.