"It's so... black!" said Ford Prefect. "You can hardly make out its shape... light just seems to fall into it!" "That," he said, "that... is really bad for the eyes." It was a ship of classic, simple design, like a flattened salmon, twenty yards long, very clean, very sleek. There was just one remarkable thing about it: it's sole purpose was to fly into the sun to provide spectacular effects for a rock concert. The blackness of it was so extreme that it was almost impossible to tell how close you were standing to it. "Your eyes just slide off it..." said Ford in wonder.
I was going to suggest measuring blackness of wedges in “Disaster Area’s”, but Procol Harum’s seem to roll of the tongue better.
That wedge was .5 on the Procol Harum sectrum
