In every one of the prints from a roll of film I shot at the Killing Fields and the Tuol Sleng Genocide Museum in Cambodia, two images overlap each other like shadows, or ghosts. In one picture, a friend holds her camera up to photograph me, and she is overlaid by rows and rows of skulls in the monument at the Killing Fields. Another friend gazes out of the frame amid clothes, bones and teeth protruding from the ground around a tree stump. Cambodian children flashing smiles in front of mass graves are superimposed on pages of my journal. The effect is so eerie that it takes me a while to realize I am looking at double exposures—I must have put that roll of film through my camera twice.

If a picture is worth a thousand words, what about two overlapping pictures? Do the words from each image conjoin, or do they distort each other, creating one intangible and meaningless image?

A photograph is a record of the light that passes through the shutter of a camera at a given instant. Our memory does that too, but it also makes and stores a fabricated record of the instant, a collection of translucent images that stack up over time, and we can “see” them all at once. Did the June bug land on my hand before or after dinner? Who walked with me down that winding trail? The many overlapping images preclude the accurate recall of a particular moment, but the effect of the layers is much more true to my memory of the trip to Cambodia. —Lu Qi