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From: moroney@jon.DEC (Mike Moroney)
Newsgroups: net.games.frp
Subject: Re: Infravision from a physical point of view
Message-ID: <1160@decwrl.UUCP>
Date: Mon, 18-Mar-85 20:04:12 EST
Article-I.D.: decwrl.1160
Posted: Mon Mar 18 20:04:12 1985
Date-Received: Fri, 22-Mar-85 23:47:40 EST
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>Effecively infravision is just another colour. The normal human eye can
>see in the electromagnetic spectrum from red to violet so extend this
>to from infra-red to (possibly ultra-) violet. Things like ``switching''
>Infravision and off and ``concentrating on infravision'' and `letting
>your eyes adjust'' just don't make sense.  Your eyes adjust to the dark
>because of the difference in brightness, not colour.

Not exactly true.  In the human eye, the sensitivity to color IS dependant
on the amount of available light.  When it gets dark enough, the color
sensing portion of the eye doesn't have enough light to operate and we lose
our ability to differentiate colors and we see in black and white.  Not
only that, the low-light sensing portion of the eye cannot sense red, so
in the dark, humans lose ALL ability to sense red.  If you don't believe me,
take some bright red object into a dark room with you and look at it. What
color does it look like?  That's right, BLACK as COAL.  As far as the eye is
concerned, it isn't reflecting any light in the visible range.  Granted, this
is the exact opposite of what infravision is described as, so it's a little
confusing.

>The old trick of casting continual light on a stone and hanging it in a
>lantern should work without spoiling infravision.

Not necessarily.  Imagine one of those "glow-in-the-dark" toys that glow
green in the dark.  In normal light, they appear white from the reflected
light, even though they are still glowing.  If infravision worked the same way,
it is possible normal light could overpower it, especially if the elven eye
was BARELY sensitive to infrared.  That makes some sense, since infravision is
only good to 60-90 feet, and the bodies being sensed are as bright as a 100 watt
light bulb in the infrared.

"There's a madness to my method."			Mike Moroney
						..decwrl!rhea!jon!moroney