How is the ExpoDisc hand calibrated?
Each ExpoDisc is assembled by hand and individually checked for total light transmission and for light transmission neutrality at our facility in Watsonville, CA. The target WHITE DENSITY RATING is 0.745 which corresponds to an 18% reflectance of incident light. This density (18% reflectance) falls within Zone V ± 1/6 f/stop. Zone V ± 1/6 f/stop has a range of 0.695 to 0.795. This information is printed on the card for the customers reference only. No adjustments need to be made. The RGB numbers represent the density of light measured at specific wavelengths in the visible spectrum. These numbers are intended only as a quality control mechanism to ensure that each ExpoDisc is within our specifications.
