R&D Report 1955-25 : The subjective white point under the condition of no adaptation. W.N. Sproson Four experiments are described in which the white point or colour balance point has been determined. It is shown that while they do not agree in their results, there is a strong correlation when the white point is considered in terms of the average value of the colour temperatures used in a given experiment. The results suggest that various types of colour film will project quite satisfactorily over a wide range of colour temperatures in spite of the manufacturers' efforts to balance the film for a specific type of lighting. Illuminant C* is considered to be appreciably blue for viewing colour pictures under the condition of no adaptation. The optimum white point would appear to have a colour temperature of approximately 5000° K.