The detection of fingermarks on porous surfaces that have been wet is currently limited to only one routine technique, Physical Developer (PD). PD is a well-established fingermark development method that has a plethora of issues associated with its use, principally based around the preparation and relative instability of the working solution and lack of contrast on dark substrates as it is non-luminescent. While these issues have been mostly addressed at an operational level, in-depth chemical remedies for the PD process cannot be devised because the mechanisms and specific targets of PD remain largely unknown. This highlights the need to understand the fundamental chemistry of the technique to recognise what may be improved and what complementary detection methods could be applied to ensure that the maximum number of available fingermarks are developed in casework.