How to measure light in a room ?
A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph. Typically a light meter will include a computer, either digital or analog, which allows the photographer to determine which shutter speed and f-number should be selected for an optimum exposure, given a certain lighting situation and film speed.
Light meters are also used in the fields of cinematography and scenic design, in order to determine the optimum light level for a scene. They are used in the general field of lighting, where they can help to reduce the amount of waste light used in the home, light pollution outdoors, and plant growing to ensure proper light levels.
Measure the distance from the floor to the ceiling if you don't already know your ceiling height (or aren't sure). Write this down on your paper. Your room light needs to hang between 30 and 34 inches above your room if your ceilings are 8 feet tall, 33 to 37 inches for a 9-foot ceiling, and an additional 3 inches for every foot taller your ceiling is.