A study of the time-integrated reflectivity of Al targets during laser-induced back ablation by 1064 nm, 10 ns laser pulses is reported. The Al target reflectance data is analyzed using a model which includes not only Al surface removal but also the possible production of Al plasma. Calculations based on a sharp Al film ablation fluence(Jth≈710 mJ/cm2)threshold agree with the reflectance data. Plasma reflectance contribution is found to be negligible for plasma electron densities of less than 0.3 critical density. ©1997 American Institute of Physics.