Beginning in 1829 and continuing into the 1880s, Robert Hunt was a scientific writer, with interests in many fields. As early as 1840 Robert Hunt was writing about photography and conducting his own photographic researches. In 1841 he published the first English treatise on photography, and during the same year he delivered a paper to the Chemical Section of the British Association on the photographic effect of ferrocyanate of potash on silver iodide.
In 1842 Robert Hunt devised the photographic process of chromatype, used in later photographic methods.
In other writings of the 1840s Robert Hunt described the Energiatype and Chromo-Cyanatype processes, and in 1844 his major work, Researches on Light, appeared. In 1845 Robert Hunt devised an actinograph along the lines of Herschel's, and in 1850 he delivered his paper "On the Present State of Our Knowledge of the Chemical Action of the Solar Radiations," an important historical account.