Anthotypes

October 17, 2018

The anthotype process, developed in the 1840’s by John Herschel, involves making photographic prints using natural plan pigments. In this printing out process, a negative is placed over a sheet of watercolor paper that has been painted with a natural dye from a fruit, spice, or vegetable. The anthotype is placed in the sun, and the ultraviolet light from the sun breaks the double bonds in the pigment causing it to fade everywhere the negative is clear. The black portions of the negative will block the UV light and the dye will remain unfaded under those parts. This creates a monochromatic image of the subject. Since natural dyes are inherently unstable, these images fade slowly over time in light when they are displayed.

Our students brought in a number of different plants, vegetables, fruits, and spices to test. They extracted the dyes using alcohol, water, or a mixture of both alcohol and water. These solutions were then painted in one of the eight squares on their test sheet. A negative of a brick wall was placed over the test paper and the paper was hung in the window. Over a period of five days, students recorded the UV readings using a UV meter and checked their print for fading.

Once the initial test was completed, the students chose a dye to work with, extracted it, painted it on an paper, created a digital negative, and set the anthotype up outside to start the fading process. Their initial results were good, but many of the prints lacked contrast because to little dye was used on the sheet.

Students were given another opportunity to create a “final” anthotype. Many students chose to adjust the pH of their dyes to change the color. One student, reduced the volume of her extract by heating it, to increase the dye concentration. Another student used a combination of different dyes. Finally, a third student developed a method of applying acid and base crystals to the paper to create interesting texture and color combinations.