Reflected Light Measurement

Illumination ratio can be varied by keeping the main light fixed and varying the fill in light.

Reflected light measurement is employed for the following purposes. a. Luminance range adjustment.

b.Self-lighted subjects such as neon signs which can only be measured by reflected light method and locations such as show windows where meter cannot be brought into proximity

with subject to allow incident light method. Measurement in these type situations in described below. 1. Luminance range center point

Refers to measuring subject luminance by reflected light method. This luminance varies somewhat according to incident light strength and surface reflectivity of the subject. Incident light becomes measured by taking the standard surface reflection as 18%, from which the exposure value is determined.

To obtain accurate exposures, the Lumisphere is used to measure effective footcandles to determine the Luminance center point.