Light in the Dark

Henrike Holdrege

From In Context #29 (Spring, 2013) | View article as PDF

I vividly remember a visit to an art museum in the early 1980s in West Berlin, Germany. In one of the great halls a room had been built, with walls, ceiling, and well-designed entrance and exit. When I entered that room I found myself in darkness. Other people were also there. I could hear them, but I hardly saw them. Suddenly a person moving about was lit up, visible in all her colors. Moving a little further, she disappeared in the dark again. It impressed me that, when nobody occupied that magic space, we could not know it was there.

This observation has stayed with me ever since. It taught me to pay attention, in nature and in my home, to related phenomena. I often marveled at how the museum installation was done. Now, after years of studying phenomenological optics, I know how the design of such a room must look. In the summer of 2012, during a course at The Nature Institute dealing with light and color, I managed to arrange a successful demonstration akin to that in the museum in Berlin thirty years ago.

During the first morning of the weeklong course we worked in a carefully prepared classroom. Each of its three windows and three glass doors had been completely blacked out. At the beginning of the second day, I asked the course participants to come again into that dark room. They took a seat. The chairs were arranged so that everyone faced a table at one end of the room. On that table they glimpsed some black and dark-blue things. But we immediately closed the door and switched off the lights, enveloping us all in black darkness. Nothing could be seen. Nobody spoke. Suddenly a crystal glowed. Seemingly out of nowhere it hovered in the air and shone in dazzling brightness. It disappeared and then appeared again. Everyone saw it and was amazed. To some it seemed they could reach out and touch it. Others saw it a few yards away, and still others saw it so far away that it would have to have been in the yard outside the classroom.

All the materials I used for the demonstration are easy to find. However, I carefully chose a certain crystal. It was a relatively large Iceland spar with regular faces. It was colorless, translucent, but with enough irregularities to be altogether bright when illumined. The light penetrated it. In its clarity of form and its transparency such a crystal is the best object I can think of to make the light manifest in such a demonstration. Crystal and light have a kinship. When we saw it shining in the otherwise completely dark room it made a deep impression on all of us.

To prepare the demonstration I placed two cardboard tubes on a table that was covered with black poster boards. One tube was short and narrow, the other long and wide. In- side and outside, the small tube was covered with black fabric and its one end was tightly closed. Its other end was open and pointed to the opening of the second tube. That tube, covered by dark fabric, had its far end closed by layers of heavy black cloth. Between the two tubes was a space. I placed a flashlight deep inside the small tube and turned it on before everyone entered the room. Its light shone into the large tube.