We have used computer simulations to explore the photon counting histogram (PCH) as a statistic for estimating kinetic parameters of a blinking immobilized fluorophore. Fluorescence trajectories made up of 500 on-off cycles allow recovery of the escape rates k(on); k(off) with 20% error, when the bin size h is in an optimal range. The corresponding estimates of the intensities I-on; I-off improve with increasing resolution k(on)h; k(off)h of the on- and off-time, respectively. PCH analysis requires that the intensities I-on; I-off be well separated. The parameter estimates improve with increasing fluorescence trajectory length. (C) 2009 Elsevier B. V. All rights reserved.