Well silly thing. My place of employment buys a Kodak Gray Set every 6 months. Basically we use a light meter and gray card for a simple reflectance test. Either send the light meter out for calibration once a year or just buy new gray cards every 6 months. It meets our SOPs and ISO guide lines.
So someone not in the know asked why we buy them all the time if they don’t go bad. Our engineering manager said because he hopes that someday the woman on the front of the pack would be included. I said I preferred the woman on the back cover.
/mods, delete if this is too far outside the scope of farktography.net
//never runs out of gray cards.