Why is artificial daylight important?

We know that the colour of light is directly related to its effect on our moods, attention level and concentration ability. Artificial daylight is much whiter than normal, with a higher blue content, which has greater stimulation effects of the brain. This makes it better to work by.

However the form of light can cause glare and Clearvision specialises in producing lenses that deal with this problem. Daylight lamps and a special lens lie at the core of Virtual Daylight® .

Are there well-being effects?

We now understand the link between light and human well-being much better than even 5 years ago. We each experience a daily natural rhythm of hormones in bloodstream, which it is important to maintain good health. However to do this it is important to suppress the sleep hormone, Melatonin, during the day. Daylight, or light that is rich in blue wavelengths, is far more
effective at suppressing Melatonin than standard fluorescent light. In the winter months, when many people receive little daylight during the day, it is important that workplace lighting should support this natural process.

For nearly 100 years lighting practice was based almost entirely on visual consideration, however we now understand much more about the importance of the non-visual impact of light .

If you would like to know more about the detail of this subject, or are interesting in reading some the academic research material, please send an email to pstephenson@virtualdaylight.com

Download the Introduction to Artificial Daylight PDF. You will require Adobe Reader to view the PDF which is available free from here.

1. Why do you call it Virtual Daylight? Because several of the characteristics of natural daylight are matched by our lamp and lens combination - the appearance is similar to that from a north-facing window.     2. What are the advantages? People feel and see better in daylight. The closer we can get artificial lighting to daylight, the better the ergonomics of the workplace. Research suggests that there are both visual and health advantages to be gained from this form of lighting.     3. Are people able to see better? Probably, although this will always depend on the individual. This light is used by DeBeers for diamond sorting and by other major corporations for inspection work, indicating its suitability for areas where vision is critical.     4. What are the health advantages? These are thought to primarily derive from the biological effects of light in regulating our body clock and the circadian (daily) rhythm of our hormones. Daylight stimulates the parts of the brain engaged in this process whereas normal artificial light is quite ineffective in this function. Research suggests that the part of the light spectrum that is most biologically active is in the blue area (450-500nm). Producing light that is rich in this area is believed to produce similar human biological reactions to those from daylight.     5. Is whiter light better for vision? In the past it has been thought that warm colour light (CCT=3000k) was good for vision because the way light is measured (the lambda curve) emphasises the yellow/green part of the spectrum in lux quantity. Research over the past decade has highlighted flaws in this system and indicates that whiter light is indeed more effective for vision.     6. Does this light help with SAD? Seasonal Affective Disorder (SAD) is a clinical condition and we should therefore be careful in make general statements in this context. Certainly light therapy has been found to be effective in controlling the symptoms of SAD in many instances. Absence of daylight is also implicated as a cause of SAD. We consider that daylight type lighting in the workplace can help with SAD, but we would not make any specific claims in this regard. We think that the effect of better lighting will help people with sub-syndromal winter blues, whose lowness during the dark months is also related to poor light conditions.     7. Is Virtual Daylight a generic name? No, it is a trademark of Clearvision International and refers to lighting products using daylight lamps and Clearvision's patented polarising lens (Optika/VDT) technology. Use of the term Virtual Daylight® by other parties is only permissible with agreement from Clearvision.     8. Is the light high in UV? Daylight lamps emit a significant amount of UV light. The Clearvision lens filters out all of this UV except for some UVA that is close to the visible spectrum (>385nm).     9. Why not just use daylight lamps Daylight lamps can be a source of glare because the eye is sensitive to white light. The polarising lens works well in reducing this glare as well a providing higher contrast, controlled distribution and low lamp read. In short the lens produces a much better lighting product.     10. What sort of control gear is used? Always high frequency (>25KHz) electronic gear to eliminate flicker, hum and excess heat from inefficient gear losses. Electricity consumption is significantly lower than on electromagnetic gear.     11. What is polarisation? Specifically it is light that is skewed towards the vertical plane of polarisation. Unpolarised light has around 50% of photons in the horizontal plane and 50% in the vertical plane. Those in the vertical plane are more absorbable by surfaces than those in the horizontal. Increasing the vertical polarisation proportion, and thus greater absorption and less reflected glare, produces better viewing conditions.     12. Is daylight polarised? Yes, although the degree of polarisation alters by weather, day and season. As sunlight passes through the atmosphere it is refracted through layers of differing density, with each refraction having a small polarising effect. Clouds scatter the light and reduce polarisation.     13. How does Virtual Daylight® fit in with LG3:2001? Very well. The principles of LG3:2001 state that glare should be controlled - the lens prevents direct lamp views - and that walls and ceiling should be kept bright - the wide distribution of the lens provides well lit walls. LG3 talks of graduated brightness, which the lens also achieves. LG3 requires a design process and so it is not possible to guarantee compliance by using Virtual Daylight (as is so with any other lighting product), however it a good contributor to a compliant lighting scheme.     14. How big is the range of light fittings with Virtual Daylight®? The range includes standard modular lighting as well surface and suspended fittings. The range has been expanded to cover a range of applications, budgets and appearance. Please ask for a catalogue or visit the product section of the website (www.virtualdaylight.com) for more information on the products available.