Immediately after Zuma I made some rather straightforward photographs of the abandoned MGM Studios New York City back lot, in Culver City, Los Angeles. These were in black and white. I then decided to try something entirely different and around 1980 I started a body of work about things you can't photograph: Gravity, Magnetism, which way water drains, and the things I see when I press my eyes with the palms of my hands. All of these images required the construction of some kind of visual metaphor. At the same time, I was switching from color negative that I was using for Zuma to large format color transparency. I had become aware that the early C-type color prints faded badly and was trying to use a new, more stable material. This was Cibachrome, which printed from transparencies. It was very industrial and artificial, with deep color saturation and contrast. It was a very flawed material for conventional images but with unique properties that I ended up embracing for the Chroma images.