By the light of a dying fire.
This picture was taken in the dark. All the lights were out, late at night. Coals in the fireplace were barely visible, glowing a dim red. The exposure was 20 seconds long, taken with an infrared camera. What glows dimly in visible light, is much brighter in the infrared spectrum. The color of the image is called “false color” sort of an artifact of the of the mixing of the infrared light and the small amounts of visible light the camera can still record.