Two possible techniques for the measurement of erosion/redeposition in the new JET divertor have been assessed; colour fringe analysis (CFA) and speckle interferometry. CFA is a simple technique in which the target is viewed with a colour camera, and can study deposited films up to 1µm in thickness. Speckle interferometry is a powerful technique for following changes in surface topology, but its sensitivity of >1µm makes it more ideally suited to the next generation of tokamaks.