Full spectrum lighting is light that contains the full visible light spectrum, similar to natural sunlight.

There is no agreed-upon definition of what constitutes a full spectrum light bulb, but it is generally understood that a full spectrum light bulb replicates some of the most important qualities of natural light. Color rendering index and color temperature represent two of the most essential and distinguishing values to determine how close a light source is to natural daylight.

Full spectrum light sources

  1. Have a color rendering index (CRI) between 91 and 97. The color rendering index is a measure of the ability of a light source to accurately reproduce the colors of various objects as compared with daylight. The index ranges from 0 to 100, 100 being the highest, and that of natural daylight.

  2. Have a color temperature between 5000K and 6500K. Represented in degrees Kelvin, natural sunlight at noon is about 5600-6500K, though this number shifts according to location and time of year. In general, the higher the color temperature, the bluer the light will appear, while the lower the color temperature, the yellower or redder the light will appear.

History and Research 

Scientific research in the 1960s has demonstrated the remarkable effects specific wavelengths of light have on all living things. Research has concluded that light with the entire visible spectrum of light wavelengths, from infrared to ultraviolet is best for vision, well being, and overall health. In the absence of sunlight, however, a light source containing a fuller spectrum of visible light, particularly the blue wavelengths, has just the same effect on plants as natural sunlight would. And, just as plants need the sun and its full spectrum light to stimulate growth, so do we as humans need full spectrum light to trigger biological processes which in turn promote focus, energy, and a better overall mood. 


Since we know that a lack of sunlight decreases health and vitality, but we live much of our lives indoors, we should at least aim to get the most out of our light sources. This is why we believe all lighting should be replaced with its full spectrum equivalent! Short of that, full spectrum light bulbs should be used when access to natural lighting is difficult or not available. 

People perceive colors differently, so the right full spectrum light bulb is a question of personal preference in addition to the intended application and use.

Apart from making for a beautiful home and improving how we see and feel at any time of the year, full spectrum light bulbs are also crucial for applications where high color rendering is essential, such as in art or photography.

For residential applications, people may prefer a warmer light with a color temperature ranging between 3500K and 4500K as this color range is comforting and pleasing to the eye, while still delivering useful benefits of full spectrum lighting. All our Chromalux bulbs fall in this range, with our Chromalux incandescents at 3750K and our halogens at 4200K.

For retail applications, people may want to choose a light source with a color temperature ranging from 4000K to 5000K. In the office, aim for between 5000K and 6500K to increase alertness.

In the end, no matter the type of full spectrum light you choose, by seeing and feeling better, you will enjoy doing what you love with increased comfort and joy under a better light. Now that’s a real recipe for health and well-being!