Convert centimeter-candle [cm*c] to candela steradian/sq. meter Online | Free lllumination Converter

A Historical Unit of Illuminance

The centimeter-candle (cm·c) is an older, non-SI unit of illuminance that measures the luminous flux falling on a surface area of one square centimeter. It is defined as the illuminance produced at a distance of one centimeter from a uniform point source of one candlepower (now replaced by the candela).

Since the centimeter-candle measures light intensity over a very small area, it represents a much finer scale compared to more common units like the foot-candle or lux. One centimeter-candle is equivalent to 10,000 lux because one square meter contains 10,000 square centimeters.

Historically, the centimeter-candle was used in photometry and lighting sciences before international standardization led to the widespread adoption of the lux as the preferred illuminance unit. Its usage today is rare and mostly of historical interest, but it remains useful for understanding older lighting data and certain precise scientific contexts where small-area measurements matter.

Understanding centimeter-candle helps bridge the gap between historical and modern units of light measurement and offers insight into the evolution of photometric standards.

Understanding Radiance

Candela steradian per square meter (cd·sr/m²) is a unit of radiance, which measures the amount of light power emitted, reflected, or transmitted from a surface in a specific direction per unit area. It combines the candela (cd), which quantifies luminous intensity, with the steradian (sr), the unit of solid angle, and divides by the surface area in square meters.

Radiance describes how bright a surface appears when viewed from a particular direction and is critical in fields such as optics, imaging, computer graphics, and remote sensing. Unlike illuminance (which measures light falling on a surface), radiance tells us about the directional brightness coming off or through a surface.

This unit helps in characterizing light sources and reflective surfaces, allowing scientists and engineers to model how light behaves in complex environments. It is essential for designing lighting systems, calibrating cameras, and simulating realistic visual scenes.

Understanding candela steradian per square meter allows precise control over brightness and directional light properties, supporting advancements in display technology, vision science, and photometric measurements.