This work reports a spectroscopic investigation on controlled size latex particle solutions. Theoretical estimates of scattering coefficients and g-factor have been obtained by Mie theory. The measurements have been carried on using time-resolved transmittance technique. Numerical evaluation of optical properties have been obtained from a comparison between experimental data and analytical solutions to diffusion equation. A Ti:Sa laser system (pulse duration: 100 fs; repetition rate: 76 MHz; average power: 1.5 W at 800 nm; investigated range: 790 - 920 nm) and a streak camera with a temporal resolution of few picoseconds have been used. The experimental results allowed us to analyse the applicability of Mie theory when different wavelengths, particle sizes, and scattering conditions are under investigation.