Color rendering of LED

22 12 2014

During four million years the human eye has intended to see every target under full spectrum lighting, that is under daylight lighting, where are all seven rainbow colors and millions of colors between them and where the light temperature is ca. 5500 K. Here is a  example of good quality spectrum:


Here is another way to show the spectrum:


The spectrum is continuous. I will get soon i little better led strip but this is already acceptable. The CRI should be as high as possible.

However, people are buying LED lamps without the knowledge or light spectrum and color rendering. They are more important than the lumen output. The price is too often more important, although we know that the cheap led costs already during 3-5 years more than a little more expensive led. The spectrum is the most important instrument for light quality. People are living years and years under light with bad quality. The experts in lighting suspect health problems from the cheap LEDs, especially to the children and in countries where there is too little daylight under winter time. Here is an warning example of insufficient light spectrum.


The architects and lighting designers must understand, how big responsibility they have. If they do not make right choices, the risk for making people sick is big.

The influence of lighting to our health 

The research scientist Christian Cajochen at the Basel university tells that the artificial light could have very negative effects. We should concern to the light as a medicine. The quality must be correct, the dose must be correct. The lighting biologists have suggested that we must specify limit values to artificial light, which spectrum is not continuous. Should we limit the staying under conventional lighting? Whos job is to decide the limits? These questions are very important to those people, who cannot get their daily daylight dose because they cannot walk under daylight and sunshine. The light is not only the aid for seeing. It can be also food, vitamin – or even poison. So tells Christian Cajochen.

If you like to discuss more about this subject, please contact