The concept of <answer>emissivity</answer> is important in understanding the infrared emissions of objects. This is a property of a surface that describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not show the same infrared image if they have differing <answer>emissivity</answer>. For example, for any pre-set <answer>emissivity</answer> value, objects with higher <answer>emissivity</answer> will appear hotter, and those with a lower <answer>emissivity</answer> will appear cooler. For that reason, incorrect selection of <answer>emissivity</answer> will give inaccurate results when using infrared cameras and pyrometers.
What is the term for the property that describes how a surface's thermal emissions deviate from the ideal of a black body?
emissivity