Originally posted by memorygap
I know that there are devices which shift or replace wavelengths of light that are out of the visible spectrum so that we can see them.
Generally, there are no such devices. When you use an infrared camera, you're using a CCD sensor or film which is sensitive to infrared light. Later, you use the electrical signals from the CCD to generate a picture on a computer screen, or you shine a light through the developed film to see the image. The actual infrared photons were destroyed when the exposure was performed. The image you see on the screen or on the photo is made of new visible photons which have essentially nothing to do with the original photons.
What would be the result of having a device which can sense artificial light bypass the restrictions of our eyes and send impulses directly to our brain. If our brains would even be able to comprehend these impulses, what would they look like? Would we see new colors
Let's think about how our brains perceive color. We have three light-sensitive pigments in our eyes, which are most sensitive to red, green, and blue light. We actually do not sense colors like yellow directly -- it happens that yellow light stimulates the red and green pigments equally, and our brain calls that equal stimulation 'yellow.' You can achieve the exact same result by showing a person a combination of red and green light. It is very interesting that our visual system is not capable of differentiating genuine yellow photons from a combination of red and green photons. Obviously, red and green photons are not at all the same as real yellow photons -- but the stimulation experienced by our retinas is the same. You might want to note that your computer monitor is actually totally incapable of producing real yellow light!
We could make the assumption that the visual cortex is built with the same features as the retina -- the visual cortex expects three channels of information, corresponding to the three pigments in the retina. There is no room, say, for a fourth channel. There is no room for 'new colors.'
If you wired up your infrared or ultraviolet sensor to the brain, you'd be stimulating one or more of those channels. Let's say, in the simplest case, you only use one -- the red channel. The information from the sensor would be perceived as... you got it -- red light.
If our brains couldn't recognise the new impulses, if such a device were used on a newly born child, would it develop the ability to sense an enlarged visible spectrum?
The adult brain would only be able to recognize the impulses in the context of its wiring -- which means it wouldn't separate the new data from optical data and invent new colors.
A baby's developing brain, on the other hand, might have the capacity to create new 'color channels' and make up new colors. This brings up the concept that the experience I call 'yellow' may in fact not be the same experience that you call 'yellow.' We both attach the same name to our respective experiences, and thus agree on what yellow is, but it's entirely possible that colors are actually experienced differently in different people's brains.
And another thing. Let's say an object, a box for example, were to be created with a material which only reflected say ultraviolet light, with our normal vision would this object be the blackest of blacks and have no shadows or noticeable depth to it?
If it reflected -zero- visible light, yes, it would be very black. There are actually a lot of uses for such substances, and there are even research teams working on designing the ultimate black surfaces.
- Warren
