Defining the visual adaptation field for mesopic photometry: How does a high-luminance source affect peripheral adaptation?

CIE 191:2010 recommends a mesopic photometry system in which the luminous efficiency function is determined from the adaptation luminance. However, it cannot be practically implemented because the adaptation field used to determine the adaptation luminance is not defined. Surrounding luminance effect is a key factor in defining the adaptation field. Vision experiments have been conducted to measure the surrounding luminance effect on peripheral adaptation state with a point source at various intensities placed at different positions. The results reveal that the effect can be described as veiling luminance and that the magnitude of the effect is larger than that of the foveal veiling luminance. A model for the peripheral veiling luminance proposed by Stiles and Crawford in 1937 shows the best prediction for the surrounding luminance effect.