Choosing the Right Color: 1  Light color is measured on a temperature scale referred to as Kelvin (K). 2  Lower Kelvin numbers mean the light appears more yellow; higher Kelvin numbers mean the light is whiter or bluer. 3  Most ENERGY STAR certified bulbs are made to match the color of incandescent bulbs at 2200-3000K. For a whiter light, look for bulbs marked 3500-4100K. For bluer white light, look for bulbs marked 5000-6500K.
Visible Light. Visible Light Waves Visible light waves are the only electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light.
The Color of Clouds. The color of a cloud depends primarily upon the color of the light it receives. The Earth's natural source of light is the sun which provides 'white' light. White light combines all of the colors in the 'visible spectrum', which is the range of colors we can see. Each color in the visible spectrum represents electromagnetic waves of differing lengths. The colors change as the wavelength increases from violet to indigo to blue, green, yellow, orange, red and deep red.