Lightbulb's energy can color you happy
Did you know the color of a light source is based on energy being emitted from the electromagnetic spectrum? For instance, an incandescent lightbulb is considered a "warm" light source because it emits less blue light and more energy in the long-wavelength portion (red/orange) of the visible spectrum.
One way to measure the "warmness" or "coolness" of a light source is the correlated color temperature scale, which tells how warm (red/orange) or cool (blue) the light source appears. The higher the correlated color temperature, the cooler, or more bluish-white, the light source will appear. Seems strange, right? But if you have ever watched a piece of metal being heated up in a fire, you might have noticed how it turns red, then orange, yellow, white, and finally, when the metal is the most hot, blue.
Currently, the maximum correlated color temperature you can find in stores is 7500K, which has a blue-white tint. A regular yellow-white incandescent lightbulb typically has a color temperature between 2700K and 3000K. Natural daylight's color temperature ranges from 5000K to 7000K, while the blue lights used in this study ranged from 14000K to 17000K.