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Technical environment
Technical environment
Global standard 220V-240V/50Hz-60Hz
Standard for USA/Canada 120V/60Hz, 277V/60Hz
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Colour rendition

The quality of how colours are reproduced is called colour rendering. Line spectra have very good colour rendering. Line spectra allow only a single colour to be perceived well. Multi-line spectra render several colours of the respective spectrum well, but colour rendering is weaker in the intermediate ranges. Blue and green colours appear comparatively grey and dull in warm white incandescent light despite excellent colour rendering. However, these colour tones appear clear and luminous in the light of daylight white fluorescent lamps – despite poorer colour rendering. With the rendering of yellow and red colour tones, this phenomenon of weakening or intensifying of the colour effect is reversed.

Because the eye is able to adapt to light of the most different colour temperatures, the colour rendition must be determined dependent on the colour temperature. Tungsten halogen lamps feature very good colour rendition. The rendition quality of fluorescent lamps and metal halide lamps ranges from good to average. The degree of colour distortion against a reference light source is indicated using the colour rendition index Ra or the colour rendition grading system. The colour rendition index is only used for white colours of light.

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Colour rendition Colour rendition
Colour rendition

The same colours of light can produce a different rendition of a body colour due to different spectral constitution. Continuous spectra lead to a unifrom colour rendition. Linear spectra only correctly render a very small colour range. Multiline spectra are compiled from different linear spectra and thus improve the colour rendition. The more spectra can be bound to one linear progression, the better the colour rendition. Incandescent lamps feature a linear spectrum, while discharge lamps have a multiline spectrum.

Colour rendition

Very good colour rendition is important for
  • exhibitions
  • trade-fair stands
  • sales rooms
  • offices
  • workstations

Colour rendition

Colour rendition refers to the quality of the reproduction of colours under a given illumination. The degree of colour distortion is indicated using the colour rendition index Ra and/or the colour rendition grading system. A comparative light source with continuous spectrum serves as a reference light source, whether this be a temperature radiator of comparable colour temperature or the daylight.

Colour rendition

To enable the colour rendition of a light source to be determined, the chromatic effects of a scale of eight body colours viewed under the type of illumination being scrutinised and also under the reference illumination are calculated and related to each other. The resulting quality of colour rendition is expressed in colour rendition indices; these can relate both to the general colour rendition (Ra) as an average value or to the rendition of individual colours. The maximum index of 100 signifies ideal colour rendition as experienced with incandescent lamp light or daylight. Lower values refer to a correspondingly worse colour rendition. Linear spectra of light lead to good colour rendition. Linear spectra in general lead to a worse rendition. Multiline spectra are composed of several different linear spectra and improve the colour rendition.

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