We present a novel method for studying the changing characteristics of sebum excretion of facial skin over a 3-hour period. Sebum production can be quantified by analysis of the pore patterns formed on a sebum-sensitive tape (Sebutape®). We applied the CIE principles of reflectance colorimetry by measuring L*, a* and b* of Sebutapes every 15 min during 3 h of sebum collection. This combined technique yielded valuable new informations on the kinetics of sebum excretion, allowing the distinction between the follicular reservoir effect and the sebum flow