Infrared light is basically heat radiation. It has the lowest energy per photon and is the safest type of light. However, when it becomes dense enough, it can damage living tissue. As with most things, the right amount is beneficial, too much is harmful.
The damage done by infrared light is related to how much infrared power drops per square centimeter. Some infrared light is needed to warm the body. The infrared radiation required for the heating of the human body averages 1 milliwatt (mW) per square centimeter. When this power reaches 10 mW, it can cause eye damage. When the infrared power reaches 100 mW, it can cause damage to several layers of the skin. An uncomfortable temperature may be felt with prolonged exposure. At 1 W per square centimeter, the skin burns and produces intense pain.
Any light of sufficient intensity can damage living tissues. What makes infrared light more dangerous is that we cannot see it.
If you try to look at the sun or a bright light, you will involuntarily squint. If suddenly a very intense light is directed at you, you will close your eyes and turn your head. This is the body’s natural defense mechanism. Since we cannot see infrared light with the naked eye, it is not possible to give the same reaction no matter how bright the light is.
Infrared light will not penetrate the body when it has low intensity, it will only heat the surface of the skin. Serious health problems can occur when exposed to high-intensity infrared light.
Infrared light is used in many ways. Infrared LEDs that provide night vision to security cameras, infrared transmitters in remote controls, and infrared face scanning units in smartphones are generally safe because they have low power.
Infrared is not visible, but can be felt as heat. If you feel the heat when you step in front of the infrared light, it may be harmful for you. Any modern camera, such as cell phone camera, computer camera, video camera, can see infrared light. An ordinary cell phone camera can be used to detect infrared light sources and their intensity.
The most harmful form of infrared light is lasers that reach high intensity in a small area. This type of laser light can cause permanent damage by burning the retina without being aware of the incoming light. If high-intensity infrared light exposure is unavoidable, protective glasses must be used.
