VIEWING CONDITIONS
The appearance and colour of prints and other objects, can be affected signiicantly by the conditions under which they are viewed. All judgments about colour must, therefore, be made under conditions that are repeatable. To this end everybody involved in the colour reproduction process must use standard viewing conditions. The term term ‘standard viewing conditions' refers to an environment where the following conditions are carefully controlled:
•colour of the light source,
•intensity of the light sources,
•influence of specular reflections,
•colour of the surrounding area,
•influence of nonstandard ambient light,
•visual adaptation of the observer's eye.
Conditions which satisfy the circumstances described may be obtained by equipment that is designed and supplied in accordance with BS 950. BS 950 is the British standard specification for artificial daylight assessment of colour. The standard has two parts. Part 1 specifies an illuminant for colour matching and colour appraisal. This is the illuminant found on most print press control desks. Part 2 defines the viewing requirements applicable for the purposes of comparing proofs with the photographic original. Conditions for Part 2 are normally only achieved Within a viewing booth. The illuminate that forms Part 1 of the standard is near to natural daylight (D65) and the illuminate for Part 2 is more typical of tungsten light (D50).
The International Organisation for Standards (ISO) 3664 provide an equivalent standard for viewing conditions.