Shot with a Polaroid SX-70 camera using "Fade to Black" film. This film is supposed to go entirely black after about 12 hours, and sometime before then you have to perform some surgery on the print, separating the front portion from the back, to stop development. The fun part is deciding when to halt the development.
After you separate the image, you let it dry. You can then either clean off the chemicals from the back part and reattach the front and back part together or leave the front part as a kind of transparency.
This image is just the front part, put on a scanner with the white pad on the scanner lid acting as background. The "border" is a natural artifact from the chemicals and adhesives around the edge of the print.