In custom LED lighting design, color temperature is a common term used to describe the visible characteristics of white LED flashlights. Many white LEDs produce a color temperature of approximately 5500 Kelvin, commonly referred to as "cool white". The light produced by cool white LED lights features a slight bluish tint, and appears relatively similar to that produced by some fluorescent light bulbs. Some cool white LEDs produce an even higher color temperature close to 6500 Kelvin, and project an obvious blue tint. Recently, LED manufactures have introduced white LEDs with much lower color temperatures, commonly referred to a "warm white". Warm white LED lights can produce a color temperature as low as 2800 Kelvin, and appear similar to natural sunlight. In the near future, designers of white LED flashlights will begin to incorporate warm white LED technology into their LED lighting products.
The color rendering refers to an index of the similarities of surface color illuminated by a light source, when compared to a referee source. The invention of the color rendering index provided a valuable tool to help us determine how colors appear when illuminated from various light sources. Natural sunlight on a clear day has a color rendering index of nearly 100. Objects observed under sunlight appear natural in color. Florescent lighting has a lower color rendering index, closer to 75. Colors observed under florescent lighting do not appear as natural, as they are somewhat discolored. In some white LED flashlights, color rendering is extremely critical. For example, aircraft pilots depend on muli-colored sectional maps for navigational purposes. During the night, it is important that the pilot can interpret specific colors on his or her map. Reading many of the analog instruments within the aircraft also depend upon specific color interpretation. However, many modern white LED flashlights designed for aeronautical use do not account for this factor. Flashlight manufactures continue to incorporate white LEDs into their products that result in colors appearing unnatural.
Warm white LED strins allow colors to appear more natural because of their significantly lower color temperature. In the near future, more custom LED products will begin to incorporate warm white LED technologies. Cool white LEDs may continue to appear in lighting applications where the appearance of color is less critical, such as LED street lamps. Warm white LED technology is relatively new, and unfortunately has its disadvantages. Warm white LEDs tend to lack slightly behind cool white LEDs in energy efficiency. Therefore, some lighting applications may require extra warm white LED strings to achieve an equivalent luminous output. The case study proving that many people feel more comfortable within environments illuminated by natural light suggests that light color temperatures can actually affect our mood. It makes sense that the warm white LED will continue to grow in popularity as LED technology continue to advance. Our engineering team at Lunar Accents Design highly encourages product designs utilizing warm white LED technology.