How can Lamp Brightness be defined?
The light output of a lamp can be measured in terms of radiometric or photometric quantities. Radiometric quantities measure the total light output power of the lamp, regardless of wavelength. However, the human eye does not sense all wavelengths. Therefore, EL lamp brightness, or luminance, is usually specified in terms of photometric units, which account for the eyes’ sensitivity. Values of luminance are usually given in units of Foot-Lambert [FL] i.e. [lm/ft2], or [Apostilb] i.e. [lm/m2], or [Nit] i.e. Candela/m2 [Cd/m2], etc. Since potential customers may not have the sensitive instruments to measure the brightness, we only can use a comparative approach and sample confirmation to finalize the brightness desired by the customer.
