a red stage lighting filter, does it produce ir light?
Every object which isn't cold enough to freeze your hand off and which isn't idealized as a white body will produce infrared rays (notice I don't call it infrared light). Side note: I only consider something to be light if it is visible to humans. It is called black body radiation. At any reasonable temperature, a body's surface emits electromagnetic waves as per a theoretical function describing intensity as a function of temperature and frequency. No object is a true black body, so the intensity is somewhat reduced for real objects. No object is a true white body either, so there is always some emitting of infrared. Just so you know, filters aren't designed to produce light. Filters selectively absorb light based on frequency, and transmit what is left-over. The production of infrared rays of the filter is a thermal phenomena. We cannot perceive this because we cannot see electromagnetic waves outside the visible light portion of the spectrum.
No. Red light is within the visible spectrum, while infrared light has a longer wavelength and cannot be viewed by the human eye.
If it did, the IR would have to be passed by the filter. A filter does not PRODUCE IR, but may separate it from all other light wavelengths if it is present with them, so nothing is visible to the eye.
no it will not.but some camera can see infrared light even an cellphone camera. Try to video the tip of a t.v remote controll which emmits infrared light it glows.
It can produce some infrared. All light contains some infrared. The filter is just allowing you to see the part of light that is transitioning from white toward infrared. There is some light passing into the infrared spectrum. Infrared goes from a dim visible red to invisible. People get confused by this and think infrared can only be invisible to the human eye. While most of the spectrum falls within the invisible a small portion is visible. Infrared means below red. As the spectrum changes from red it becomes infrared. Light is always in the light spectrum. It just happens that some light sources are better at emitting infrared frequencies. 0.7 - 300 micrometers is the infrared spectrum. Some red light can fall close to or in to this spectrum. The heating bulbs you can see in some restaurant kitchens are using infrared for heat. This is visible to the eye. This an incomplete picture of infrared but the point is red spotlights are producing it like all spotlights are producing it, it's just not, with a filter, entering into the spectrum of infrared at any greater frequency than white light is. It merely shows the spectrum closest to infrared. It just won't happen to have more. So to answer the question, yes and no. Really close but no big cigar.
