We have shown by use of HRS spectroscopy that AgBr nanoparticles exhibit a first hyperpolarizability comparable to materials under consideration for optical technology applications. The technique enabled us to discover the unexpected quantitative conversion of AgBr into the Ag(TAI) complex on treating AgBr nanoparticles with TAI. This result suggests that TAI may function as a silver halide solvent under photographic conditions, with hitherto unconsidered consequences for grain architectural features of small radius. Results on dye adsorption demonstrate that HRS may be a powerful analytical tool for studying the adsorption of dyes on photographic silver halide grain surfaces. From the spectral dispersion of the HRS signals we can identify resonances with electronic transitions of the dyed and undyed particles. These transitions may also be important in their photophysics.