A hypothetical escapade into negative light
by Billy Gard
Turn on a flashlight, and it shines darkness? Well then we better call it a flashdark. This may sound like the escapade of a runaway imagination, but Tim Simon, our main character on the hypothetical island of Burtain, finally invented a lamp that shines darkness. When you shine a conventional light on the wall you will see a spot of light on it. And you know if you put your hand in the way you will see a shadow of your hand. Now, suppose you shine a "flashdark" on the wall. What you see will look like what we call a shadow, but shaped like a light spot. Now here is the neat part. Suppose you put your hand in the way of it (no, you won't get burned. A dark beam is not hot, at least as far as I know). What you will naturally see is a "reverse shadow" of your hand, a light image of your hand against the dark spot produced by the "lamp". I guess that would be called a shinow
Now all this may sound like a hypothetical generalization of the usual behavior of light. But let me explain. You know about the visible portion of the electromagnietic spectrum, the part that causes the sensation of light in the eye. When a light beam falls on the photoreceptors it causes them to send a message to the brain that says "light". Now somewhere on the electromagnetic spectrum Simon seems to have discovered a wavelength that deadens the photo response of the receptors it falls on. So naturally those receptors will send a weakened response to the brain relative to the surrounding receptors, causing it to seem that less light actually fell on those receptors. Because of the light-suppressing effect of this ray it very much amounts to a beam that can shine shadows on the wall.
You can imagine a movie theater that uses a dark beam projector to create the pictures. Instead of turning off the house lights, they will haven generous, "reading level" brighteness in the theater. Then they turn on the dark projector and you see "shadow pictures" on the screen. And if the film affects the dark beam the same way it does light, I suppose the picture will be a negative. This is why they will probably have to use the negative of the filmstrip for projection purposes.
Now, by now you readers may be wondering about another way this new innovation can parallel with the nature of conventional light: Can darkness be shined in color? Well Simon found also that the particular color receptors affected varies with the wavelength, just as is the case with the light wavelengths. If you can pick frequencies that let you supress one receptor type at a time, you can cast shadows that are majenta, yellow and cyan, which are the same colors used as pigment primaries in printing. With just these, you can have full color darkness!
Probably the most mystifying example of color darkness can be seen by shining a flashdark through a prism. Roy G. Biv meet your evil twin brother. Look on the wall and you see a colorful shadow, with the colors cyan, blue, magenta, red and yellow. I hold that the wavelength ranges that suppress the three color receptors overlap in much the same way as those which stimulate the receptors. The result would be something akin to a pigmental color spectrum, a negative rainbow if you please.
Now getting off of the hypothetical island of Burtain, let us get into the real world of confirmed science and optics. Let's think of ways that beams of darkness could actually be realised. In an environment of directional light, this is easy. Sometimes when the sun is setting over mountains, you can see what looks like a dark beam streaming from a mountain top. Now of course that is merely a meridian in which the light of the sun is blocked by a mountain. But this is only a partial realization, since it is still lightbeams that are being shined, and what looks like a darkbeam is only a selective blocking of the beam.
A more true case of shined darkness is to be found in in a diffuse light environment, but it may be difficult, if even possible, to see them. If you are in a room with diffuse light, such as one with white walls and a ceiling full of panel flourescent lights, the introduction of a dark object into the room will in fact decrease the total light, since from any viewpoint you are seeing that dark object instead of the white wall directly behind it. Now it is hardly noticeable by casual observation. But technically the object could be considered a point source of darkness, although the dark shines in all directions.
But suppose now that we would make this shined darkness directional. Let us construct a device: a white box, translucent so its interior is about as light as the surrounding environment. On one end of the box is an opening covered by a lens with its focal length half the box's length. This way, a point source of light in the center of the box would form a directional shaft of light out of the lens. Now replace that light source in the box with a pitch black object in exactly the same position. Now you should see the black color of the object through the lens, but only if you look along the lens's axis. At all other angles you only see the white color of the box interior. At least theoretically, a dark spot should appear on the wall in the direction pointed at by the lens. In effect you have created a flashdark. Now I suppose you could make three of these box instruments and inside each put a different strongly colored object: magenta, yellow and cyan. Now you should be able to shine three colored shadows onto the wall in these three colors, and mix them subtractively.
Simple mathematics would show why this should work. The room is white; the box is white, including the interior. So from the vantage point of the spot on the wall, the lens appears black, but it looks white from all other angles. That means that the total light shining on that part of the wall is less, so it should appear darker. However, illumination difference may be too slight to notice, unless maybe you move the dark spot around on the wall. But it would be an interesting thing to try just in case!
One winter the curtains of the front window were open just a crack, and across the street was a gleaming white snow bank along the roadside. When a car drove by I could see on the wall facing the window a shadow moving across it in the opposite direction of the car. This worked as a crude pinhole projector of sorts, but it is one example of how darkness can actually be shined.
Now think of the different uses of dark rays. You can operate searchlights in the daytime, producing shadows on the clouds - but then we call them searchdarks. You can operate drive-in movies in the daytime. And if your outside and it's so bright it's blinding, you can ask for a keychain pendark so you can see what you are looking at. Sometimes it gets so bright outside that I can't see whether stoplights are red or green. That happened during a driving test! This would be a good time to use stopdarks.
And think of the new songs that will come out, like You Are the SunShade of My Life, A Walk in the White Forest, Gloom Little Gloomworm, You Dark Up My Life, This Little Dark of Mine and Keep Your Shadey Side Up. There are also barbershop standards like Shade On Harvest Moon, Me and My Shinow, In the Shine of the Old Apple Tree and Oh Shade on Me.
What if it were this way from the very beginning? "In the beginning there was just pure white. God said 'Let there be dark' and there was dark." "The wicked shall be cast into outer lightness." "Let your dark so shade before men." Brand new proverbs will come about like "It's better to dark a candle than to curse the lightness." "Rise and shade." President Bush would have to reintroduce his message as "1000 points of dark."
New movies and shows will come out like Pitchblack and the Seven Dwarfs, Village of the Blessed, Light Shadows, Creature From the White Lagoon and finally, The Sunshade Boys. There will be Tinker Bell II, a dark spot on the walls. Just for the record I was actually in a play called White Comedy. The play begins in the dark, then they have a power failure and all the lights go on for the rest of the play.
Will we ever go outside and see dark specks in the blue sky? They will be negative stars. And wow, a sun that shines darkness. When they finally invent a flashcube of this type, you will know that it means to be blinded by darkness. How about darkish curtains in the sky at noon? Those are northern darks.
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