sensitometric curve: meaning, definition, pronunciation and examples

No. While its origins are in film sensitometry, the concept is equally critical for digital sensors. Digital cameras have a similar 'opto-electronic conversion function' (OECF) which is their digital equivalent, plotting digital signal value against log exposure.

The vertical (y) axis represents the optical density (D) – how dark the developed film is. The horizontal (x) axis represents the logarithm of the exposure (log E) – the amount of light that hit the film. Hence it's often called a D-logE curve.

The 'toe' is the lower, flatter part of the curve representing underexposure, where density increases slowly. The 'shoulder' is the upper, flatter part representing overexposure, where density barely increases with more light. The straight-line section between them is where the film responds most predictably.

The foundational work was done by Ferdinand Hurter and Vero Charles Driffield (H&D) in the late 19th century. They established the scientific study of photographic materials, and the H&D curve is named after them.

A graph plotting the density of a photographic material against the logarithm of its exposure, used to characterize its response to light.

Sensitometric curve is usually technical/specialist in register.

Sensitometric curve: in British English it is pronounced /ˌsensɪtəʊˈmetrɪk kɜːv/, and in American English it is pronounced /ˌsensɪtoʊˈmetrɪk kɝːv/. Tap the audio buttons above to hear it.