CRI / Ra Value Explained: Colour Rendering in Lighting
What Is the Ra Value?
The Ra value is the most widely used measure of the Colour Rendering Index (CRI). It describes how naturally colours appear under an artificial light source compared to a reference light source. Sunlight or the light of an incandescent lamp serve as the reference – both have an Ra value of 100.
The Ra value is determined using 8 standardised test colours (R1–R8). The smaller the colour deviation under the light source being tested, the higher the Ra value. In addition, there are extended test colours R9–R14, with R9 (saturated red) being particularly relevant in practice, as many LEDs show weaknesses in rendering red tones.
What Ra Values Are There?
- Ra 100: Perfect colour rendering (sunlight, incandescent lamp, halogen lamp)
- Ra 90–99: Very good colour rendering – for demanding applications (kitchen, bathroom, workspace, hospitality, art)
- Ra 80–89: Good colour rendering – standard for living spaces and general lighting
- Ra below 80: Limited colour rendering – sufficient for warehouses, garages, outdoor areas
The European standard DIN EN 12464-1 (Lighting of Work Places) requires a minimum Ra value of 80 for most indoor applications.
Why Is the Ra Value Important?
A low Ra value makes colours appear pale, dull or distorted. This is particularly noticeable with:
- Skin tones (bathroom, vanity mirror)
- Food (kitchen, restaurants)
- Clothing and textiles (dressing room, retail)
- Art and photography
- Work areas involving colour assessment
In living spaces, a high Ra value ensures that materials, furniture and surfaces look the way they do in daylight.
Ra Value and LED
Modern LEDs easily achieve Ra values of 80 or higher. High-quality LED lamps and luminaires offer Ra 90+ and thus come very close to the colour rendering of an incandescent lamp. At Leuchtenland.com, you will find the Ra value listed in the technical specifications for every lamp.
Frequently Asked Questions (FAQ)
Is Ra 80 sufficient?
For general living space lighting, yes. For areas where colours matter – kitchen, bathroom, workspaces – Ra 90 or higher is recommended.
What is the difference between Ra and CRI?
Ra and CRI refer to the same thing: the Colour Rendering Index. CRI is the international designation, Ra is the abbreviation commonly used in Europe. Both use the same scale from 0 to 100.
Why is R9 sometimes listed separately?
R9 describes the rendering of saturated red, which is not included in the standard Ra (based on R1–R8). Many LEDs score lower on R9 than on their overall Ra. A separate R9 specification shows that the manufacturer also controls red rendering – a mark of quality.
In Summary:
The Ra value is one of the most important specifications when selecting lamps. It determines whether colours appear natural and vivid or pale and distorted. For high-quality lighting in living spaces, a minimum Ra value of 80 is recommended; for demanding applications, Ra 90 or higher. At Leuchtenland.com, you will find the Ra value in the product details of every lamp.