The absorption of light by photolytically generated silver colloid solutions is studied by thermal lens spectrophotometry. It is found that absorbance by silver nitrate solutions at 488 nm is a result of colloid formation. The absorbance is related to the particle size distribution and varies substantially from measurement to measurement even within the same colloidal solution. The shot-to-shot variance of the thermal lens signal is minimized by producing the colloid in a flowing AgNO3 solution, but still varies significantly from solution to solution at equal concentrations.
