Ackroyd & Harvey’s artistic process is similar to that of black and white photography but instead of a gray-scale they work with the controlled use of chlorophyll, or a green scale. Using a specialized paste they adhere a mixture of seedlings to a canvas. The combination provides a highly light-sensitive surface on which to project the image. The grass photographs are grown in the dark, only receiving light from a projected negative. Where the light is stronger more chlorophyll is produced and the grass is greener. Where the light is dimmer the blades will be less green. Where there is no light they will grow but stay yellow. As the small, embryonic kernels germinate and mature the image is embedded into the living material. With this technique the artists are able to create complex images on a small to large scale.
“The image in our photosynthesis works is on a molecular level. The image, or the portrait, of the person is actually inhabiting the grass. We think it just brings up lots of questions about the true nature of ourselves within nature, within landscape as well. There's something very beautiful about that. If you actually study the structure of the chlorophyll molecule, it's almost the same as the heme molecule in our blood—the atom bound at the center of chlorophyll is magnesium, and iron is held at the center of blood.”