What are Thermal Color Meanings?

Shortly answered. Thermal camera color meanings are the different temperatures that are received by the thermal imaging device. Thermal imaging colors mean that the brighter the colors that are received by the thermal imaging device, the hotter the certain object is. This is the simplest explanation, but there are a lot more things that go beyond it. Keep on reading if you are interested in finding out what exactly thermal color meanings are.

Thermal Imaging

Thermal color pictures are present with specific devices – Thermal imaging devices. Thermal imaging devices are devices that greatly boost the visibility of pitch-black dark environments by detecting the certain heat and infrared wavelengths that are emitted from almost every single object on earth, no matter if its living or not. The heat and infrared wavelengths that those objects emit is picked up by the thermal imaging device. Then the thermal imaging device gives the user of the device a colored picture which is also called a thermographic picture or thermographic pattern.

Example of Thermal Image

This thermographic picture shows the user the infrared image of the certain object. Infrared is a type of light that we cannot see or detect with our naked eyes. Our sight has the possibility of only detecting what is called visible light. Infrared light brings different kind of information to the user that cannot be gathered from visible light sources. It basically shows the user how much heat something has and gives the user a detailed information about the temperature of the object. Everything that is detectable by the thermal imaging device has a certain heat signature and emits infrared light, which the thermal imaging device can pick up.

Actually, even cold things like ice for example, emit certain heat. The image will definitely not be as bright as if you are looking at a fire for example with a thermal imaging device, but cold objects still emit heat, just a lot less of it. This leads us to a conclusion that the more heat that a certain object possesses, the more heat it emits and the colder a certain object is, logically the less heat it emits. With thermal color meanings, warmer objects basically emit much brighter colors as with colder objects they emit much darker and not as bright colors when getting picked up by the thermal imaging device.

When looking through a thermal imaging device, you take a look into the infrared world of things. Even is the sun is down and it is pitch black outside, temperature that the objects emit doesn’t just disappear, it is still there, just a bit less than compared to when the sun is out and warms things up.

For example, warm blooded animals and people try to basically keep the same body temperature during both the nighttime and the daytime. Their temperature of the body does not change when it gets cold/dark outside. They both possess a constant body temperature, no matter what the weather conditions are.


Look at it this way – when you receive a picture through the thermal imaging device, you don’t really receive a picture, you receive a thermogram. A detailed information based on temperature, which has different bright colors. In any thermogram, the brighter the colors in the thermogram are, the warmer the object is and vice-versa.

Colors that are based around red, orange and yellow glow from objects that emit much more infrared wavelengths and indicate a warmer temperature. Colors that are based around the darker part of the color spectrum like different shades of purple, dark blue and even black indicate objects that emit less infrared wavelengths and indicated that the object possesses a colder temperature.

Basically, the black or darker color spectrum that is received by the thermal imaging device represents the coldest part of the object which is around 0 degrees, the darker the object’s colors are the closer it is to 0 degrees Celsius. Moving from slightly brighter colors like red and yellow but not too bright, the object’s temperature goes to around 23.5 degrees Celsius. And for the hottest part of the thermographic picture, the brighter yellow, red and orange colors represent that the object’s temperature can even go up to 62.3 degrees Celsius.

Another thing that is very common with some thermograms is to receive a thermogram in the form of a grayscale image. This is the case where you get only black/white colors that are passing through different levels of the shade gray, to represent the main differences in temperature. This is basically used in thermographic picture of surveillance thermal imaging devices like security cameras, but not with alot of thermal imaging devices.

This is the case because for a normal person it will be very hard to distinguish the differences in temperature with only two colors present – black and white compared to a colored pallet with red, orange, yellow, black and purple.

You might also find this article interesting: 25 Myths about Thermal Technology


Practice has got to be your best choice when trying to fully understand the thermal image color meanings. Different objects appear quite different on thermal imaging devices. For instance, animals with thick fur like lions or wolves for example will appear slightly darker compared to humans for example. This is the case because the fur of those animals absorbs some of the heat and infrared wavelengths that are emitted from their bodies and they appear slightly darker compared to a human for example, even if their body temperature is exactly the same.

The main and simplest thing to keep in mind when looking at a thermogram and comprehending thermal image meanings is that the brighter the colors of the spectrum are on the thermogram, the brighter the object is. Dark colors like black, dark purple and blue represent colder objects that emit less heat and infrared wavelengths and brighter colors like red, orange, yellow and bright purple are present with objects that emit much more infrared wavelengths, have more thermographic information and in consequence have a much warmer body temperature compared to the darker-colored thermal image meanings.

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