A proof of concept study for a method of determining quantitative shunt values in silicon solar cells from photoluminescence images is presented. The method is based on interpretation of the luminescence intensity around a local shunt or recombination-active defect in terms of the extracted current. The theoretical relationship between the photoluminescence signal and the shunt current is derived. Experimental results on specifically prepared test structures show good agreement with known shunt resistance values. Experimental data on diffused wafers are presented. The effect of the front metallisation in complete cells on the appearance and interpretation of shunts in photoluminescence images is investigated experimentally. The limitations of the method are discussed. Copyright © 2012 John Wiley & Sons, Ltd.