The relationship between the optimum process control parameters for surface pressure feedback control during Langmuir-Blodgett (LB) film transfer and the properties of floating monolayers is investigated using a computerized Langmuir trough equipped with proportional-integral (PI) feedback control. The monolayer materials used in this study were arachidic acid, a crystalline solid at room temperature, carboxylic acid-terminated poly(dimethylsiloxane) (M(n) = 2100), a liquid, and carboxylic acid-terminated 1,2-hydrogenated poly(butadiene) (M(n) = 2822), a viscous liquid. The proportional (K-P) and integral (K-I) control constants as well as the barrier velocity (v) are optimized by introducing a step change to the surface pressure set point while the surface pressure vs time is recorded. A process control performance index, which calculates a positive number by integrating the initial portion of the surface pressure vs time curve, is then used to optimize the control constants. Our results show that the optimum K-P for arachidic acid is smaller than that for the other two materials by a factor of 40. This result appears to correlate strongly with the two-dimensional compressibility of the floating monolayer films. The optimum barrier velocities were also found to vary with certain monolayer material properties, while optimum K-I values did not show a strong dependence on monolayer material properties.