We propose to characterise the vertical component distribution for polymer:fullerene blend Organic Photovoltaic (OPV) films, which have been processed using environmentally friendly casting solvents. This development is of crucial significance in the transition of OPV¿s from laboratory scale devices to large area modules that can be manufactured on an industrial scale, thereby realising OPV¿s as a disruptive technology for low cost solar energy conversion. Promising solvent mixtures have been determined through a thorough analysis of the Hansen Solubility Parameters, a relatively straightforward evaluation based on the physical interaction for a solvent with each polymer component. Using this approach we have identified a number of environmentally friendly solvent mixtures suitable for high performance OPV devices.