Synthesis and application of an aqueous nile red microemulsion for the development of fingermarks on porous surfaces

•Synthesis of an oil-in-water microemulsion containing a luminescent dye, nile red.•Effective in developing fresh latent fingermarks on porous surfaces.•Equivalent performance compared to methanolic nile red formulation.•Non-toxic, much lower cost and with an extended shelf life.•Outperforms aqueous nile blue for charged and natural fresh fingermarks.