The Gossen Calculator for Panlux and Panlux 2 Meters is an old-fashioned but handy circular slide rule, and can be used with any light meter that can display lux light values.
Lux is a measurement of luminance which accounts for a quantity of light as applied over a surface, and most color meters can display lux.
Thus, if you use a color meter (or any other meter giving lux but not EV values such as conventional incident exposure meters) for your work and would like to also use it to provide exposure readings, the combination of the lux reading from your meter and this Gossen Calculator can give you a range of shutter speed and aperture values which will yield a proper exposure.
Slide rule displaying shutter speeds and apertures
Requires input of a lux value and an ISO value
Applicable to Gossen Panlux/Panlux 2, Color-Pro-3F, and any other meter displaying lux value