EI/ASA:  the sensitivity of film to light as rated numerically.

Emulsion:  the light sensitive coating on film negative, consisting of silver halide crystals suspended in gelatin. Black and white film stock contains one layer of emulsion, colors has several. The emulsion is fused on to an acetate base.

Exposure latitude:  refers to the emulsion’s ability to produce acceptable image over a range of exposures.

Frame: a single picture on a strip of film.

Negative: Raw film stock and also raw stock which has been exposed but not processed.

Sensitometry:  the science of measuring a film emulsion’s light sensitivity.

Speed: the emulsion’s sensitivity to light, expressed by the EI/ASA rating, enabling the DP to make important decisions as to which stocks to use in different lighting conditions.