Cyanotype: Pictures Printed by the Sun
In the 1840s, a new kind of picture appeared that needed no camera. It is called a cyanotype, and it makes pictures using sunlight and a special coating on paper. The result is a deep, rich blue with white shapes, a color that gave the engineer's blueprint its name.
Here is how the method works. A sheet of paper is brushed with chemicals that change when light touches them. The paper is dried in the dark. Then an object, such as a leaf, a feather, or a piece of lace, is laid on top of the paper. When the sheet sits in sunshine, the uncovered parts react to the light and turn blue. The covered parts stay pale because the object blocked the light.
Afterward the paper is rinsed in plain water, which washes away the chemicals that did not react. The blue deepens as it dries. What is left is a white outline of the object against a blue background, almost like a ghost made of light.
An English scientist and artist named Anna Atkins used the method to make careful pictures of seaweed and plants. Her work is remembered as one of the earliest uses of photographic images in a book. Today many art teachers use ready-made sun-print paper with students, because the steps are simple and the results look magical.