This process wouldn't be seen for nonporous surfaces like tile (Fig. , bottom), which lacks any absorbency. Alternately, starch present in paper from its manufacture was considered as a possible fixative for absorbed iodine, which could provide competing background colouration between the ridges of the fingermark residue. To test these theories, paper surfaces were sequentially subjected first to an iodine solution, followed by an α-naphthoflavone solution (Table ), to ensure excess iodine and heptane evaporated from the paper prior to addition of the fixative. This was found to greatly improve the quality of the ridge detail after fixation with the α-naphthoflavone solution (Fig. , top). Conversely, for nonporous tile the sequential approach resulted in weaker development, likely because the volatilisation of iodine from the surface prior to α-naphthoflavone fixing yielded a net reduction in chromophore (Fig. , bottom). As a final experiment, the copy paper surface was replaced with starch-free paper. Fingermark blurring similar to Fig. was observed on the starch-free material, ruling out the starch from paper manufacture as the cause of worsening ridge detail. A video showing the application of iodine solution to fresh fingermarks on copy paper is provided as Supporting Information.