Why are Infrared Light Incandescent Bulb mostly red?

1, infrared light incandescent bulb are mostly red light bulbs.
But because infrared lamp itself is invisible light. This red color of infrared light bulbs is more of an indication and explanation.
2. Since the infrared lamp itself is invisible, infrared light can of course be made transparent. Since infrared lamp can be emitted, thermal effects are also present.
However, due to process problems, in the manufacturing of traditional light sources (filament thermoluminescence), it is actually more difficult to process only an electric light source with a very small range of wavelengths, so it is better to expand to both sides. Then, visible red light Natural light close to the water tower.
infrared lamp