In high-voltage DC photoinjector guns, the drive laser pulse duration affects the electron bunch characteristics and is therefore an important subject for experimental investigation in order to optimise performance of the gun. Initial experimental studies into this effect have been carried out on ALICE (formerly the Energy Recovery Linac Prototype) photoinjector. During the commissioning of its DC photoinjector gun, electron bunch parameters were measured at two laser pulse durations, ~7 ps and ~28 ps FWHM. The shorter laser pulse is the intrinsic output pulse length of the laser, while the longer pulse was synthesised using a pulse stacker. The electron bunch parameters that were measured included transverse emittance, correlated and tilt compensated energy spectra and bunch length. The experimental results and their comparison with computer simulations are presented and discussed.