I'm not saying there cannot be infra red in the dark
but surely it has to have a source, a light spectrum containing some amount of infra red
and if there is no light inside a box, where would the infra red come from
but then, like someone else indicated, how little light is really needed for infra red to occur
avoid black lytics 
I'm getting confused here too, but here's what I remember from my physics...
There's a difference between absorption/reflection of incident light and intrinsic emission of light. Incident light comes from lightbulbs, the sun, etc. Intrinsic emission comes from an object's temperature.
Most of what we see is due to absorption and reflection of incident light on that object- some of the light is absorbed, some of it reflected. We see the reflected light. That's why things look different indoors under fluorescent/incandescent light than outside in sunlight, especially for photographers.
The emission of light by an object is due to its temperature (governed by Plank black body radiation/statistical mechanics). It's important to note that temperature dictates color, not the other way around. Hot metal glows red, painted red metal is not hot. A CFL lightbulb's color is stated as a temperature (ie 2700K = Kelvin).
Hope I got that right and I'm not restating anything. it's been awhile since I thought about this stuff. I can think up some examples if it helps.
There's a difference between absorption/reflection of incident light and intrinsic emission of light. Incident light comes from lightbulbs, the sun, etc. Intrinsic emission comes from an object's temperature.
Most of what we see is due to absorption and reflection of incident light on that object- some of the light is absorbed, some of it reflected. We see the reflected light. That's why things look different indoors under fluorescent/incandescent light than outside in sunlight, especially for photographers.
The emission of light by an object is due to its temperature (governed by Plank black body radiation/statistical mechanics). It's important to note that temperature dictates color, not the other way around. Hot metal glows red, painted red metal is not hot. A CFL lightbulb's color is stated as a temperature (ie 2700K = Kelvin).
Hope I got that right and I'm not restating anything. it's been awhile since I thought about this stuff. I can think up some examples if it helps.
Temperature is not the only source of emission. Transitions in outer electrons emit light too, some of which is visible. Some may be infra-red too; I'm sure a chemist can help us. A CFL bulb is not actually at 2700K - that is merely to tell us what colour it roughly mimics for the human eye. Be careful that you don't add to the confusion in this thread.
Not my intent to cause confusion obviously, sorry for that. Hopefully the rest was accurate. So I'll phrase this as a question since I'm not sure - are the electron transitions you're taking about fluorescence and phosphoresce?
use infra-red paint ... and it doesn't matter how it looks 
Maybe you wrote it as a joke , but there is such a thing as infra-red paint, or, to be more correct, considering what we are talking about here, a good infra red emitting paint, and that would be a matte black one.
By definition the best infra red (heat) emitter is called a "black body", how's that?
Black body - Wikipedia, the free encyclopedia
Notably:
, but there is such a thing as infra-red paint, or, to be more correct, considering what we are talking about here, a good infra red emitting paint, and that would be a matte black one.By definition the best infra red (heat) emitter is called a "black body", how's that?
Black body - Wikipedia, the free encyclopedia
Notably:
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