Light Sensitive Materials (contd.)
In 1727, Johann Heinrich Schulze (1687-1744), a German
scientist found that silver salts darkened when exposed to
sunlight and published results that distinguished between the
action of light and heat upon silver salts.
Even after this discovery, a method was needed to halt the
chemical reaction so the image wouldn’t darken completely.
A Simplified Schematic Representation of the Silver Halide Process