This photo of ice forming on rocks was captured by Frank Hurley during the Australasian Antarctic Expedition. It was printed by Hurley for exhibitions in London and Sydney in 1919. Hurley printed the images for these shows using the carbon printing process. The enlargements from the original negatives were made with a carbon black pigment image suspended in gelatin which hardened when exposed to light. As they used pigment rather than silver, they are generally more stable and less sensitive to light than other formats. Green and blue hues were added by toning the pigment.