Lighting intensity is measured in foot candles. How is this measurement determined?

The measurement of lighting intensity in foot candles is determined by the brightness one foot away from the light source. A foot candle is defined as the illuminance produced by one lumen spread over a one-foot square area. This means that to measure foot candles, one essentially assesses how much light falls onto a surface from a light source when the observer is positioned one foot away from that source. This measurement directly reflects the effectiveness of the lighting in illuminating a space and is essential in contexts such as interior design, photography, and safety assessments.

Understanding this concept is important, as it illustrates how lighting can create different atmospheres or how to ensure sufficient lighting for various tasks. The other factors mentioned, like distance from the wall, type of bulb used, and ambient light in the room, may influence the overall perception and effectiveness of lighting but do not determine the specific measurement of foot candles.