A study in black: The cielab and cieluv L* function for very low values of Y

Four approximations to the CIELAB and CIELUV metric lightness function L * for values of Y < 1% have been examined. It is shown that the requirement of equality in both value and first derivative at the point of transfer results in considerably poorer fit to the Munsell Renotation Value function than approximations that do not demand continuity at the point of transfer.