From Latin candidus ('white, gleaming, pure, innocent'), from candēre ('to shine, glow white'). In Roman usage, candidus was associated with transparency and purity — candidates for office wore white togas (toga candida) to symbolise integrity. The sense of 'frank and sincere' entered English in the 17th century. The photography sense developed in the 20th century from the idea of a natural, unposed (frank) image.