Stephen wrote:
> Thanks for the feedback.
> 
> But the reason I was using three lights was to get **enough** illumination.
> Just one light doesn't seem to cut it, so I'm wondering if there's something
> basically wrong in my approach or system.
> 
> So the question would be - in any typically arbitrary scene such as modeling
> a TV or a plant or a table or desk, can you illuminate the scene with one
> light source which would approximately simulate one 100W lightbulb in the
> room, at 6-18 feet away?
> 
> My answer would be - nope- need multiple lights. What's that tell you?
> 
> 
> I'll try the gamma correction right now.

 From an advanced newbie...

Realistically simulating lamplight (or any other kind of real-world 
light source) in POV-Ray is a good deal more complicated than simply 
defining a light source at a certain distance, with a certain 
value/intensity, and hoping for the best.

First of all, a default light source has no falloff. The light rays will 
be equally bright whether they're 100 units away or 10,000 units. The 
only difference is how many rays hit the object (since a default light 
source emits light in all directions, placing the light source very far 
away spreads the rays out more, thereby making an object *appear* 
darker). In reality, it's just receiving fewer beams.

However, putting your light source very close isn't always the answer 
either, since you'll have high concentrations of light beams in a small 
area, causing washed-out spots.

GrimDude is simply saying that you'll get smoother coverage with your 
lights - the rays will be more spread-out, reducing blown highlights - 
by moving your light sources farther away. I would have said exactly the 
same thing myself if I had noticed the problem (it really didn't strike 
me). When I'm not trying to achieve photorealism, I quite often put my 
lights 500+ units away, even if my object is only a few units each 
dimension. If I had a very large object, eg. 30x30x30, I would probably 
put my lights even farther, such as 800. That's just how I tend to 
operate, however. If you really want a photorealistic effect, the rules 
all change.

There are ways to make the light sources behave realistically. POV-Ray 
supports light falloff and fading, which, when set properly (an area I 
can't advise on, unfortunately) can produce quite realistic results. If 
you want to look these up, look for the 'falloff' and 'fade_distance' 
keywords in the Help file.

Incidentally, Jaime Vives Piqueres has done some research into the 
physical properties of light and has created some macros for realistic 
light simulation. I am still learning how to use them myself, but you 
might find them interesting. http://ignorancia.org/lightsys.php

Hope this helps somehow. As long as you keep in mind that I'm not an 
expert and thus take all this with a grain of salt, I think you'll be 
okay. :)

~Mike

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