- Silver salts darken when exposed to sunlight
1826 - Joseph Niepce dissolved bitumen in lavender oil on pewter.
Bitumen that was exposed to the sunlight (8 hours) hardened, whilst the unexposed bitumen remained soft
William Henry Fox Talbot - 1838
Cyanotype - cyan-blue print
Paper type
Tonal contrast
Colour
Photograms are created by the placement of objects on light-sensitive paper or film.
Once exposed to light, the shape of the object is revealed.
The proximity of the object to the paper creates sharper or softer outlines.
The transparency of the object and the amount of light used changes the intensity of the tones