Hydroquinone (HQ) was used as the principal chemical reducing agent. to prepare aqueous silver nanocolloids from silver nitrate. The data demonstrate that HQ is unable to initiate the particle growth process on its own, but is able to sustain particle growth in the presence of pre-existing metallic clusters. This unique selectivity is similar to that seen in photographic systems. Data are presented on two different approaches to initiating the HQ growth process. Very low levels of sodium borohydride can be used to form seed particles. Alternatively, the data show that controlled growth can be initiated by exposing the samples to UV radiation, relying on the photoreactivity of hydroquinone to start the process. These results were used to explore the dynamics of very dilute NaBH4 seed particles. They also were used to create nonspherical disk and triangular-plate morphologies directly from solution, without the need for subsequent reformation or template processing.