What is CRI? (Color Rendering Index)

CRI, the Color Rendering Index, is a metric that evaluates the ability of a light source to accurately reproduce the colors of various objects compared to a natural light source, such as sunlight. This index is very important when selecting lighting because it significantly affects how we perceive colors and how objects around us appear.

History and Significance of CRI

The concept of the Color Rendering Index was developed in the mid-20th century by the International Commission on Illumination (CIE). The goal was to create a standardized way to measure and compare the color rendering capabilities of different light sources. CRI values range from 0 to 100, with 100 representing perfectly natural light, like sunlight.

Practical Use of CRI

CRI is an important factor in various fields:

At home and in offices: High CRI lights (90 and above) are preferred to ensure comfortable and accurate color rendering.
In retail: Stores and supermarkets use high CRI lights to make products look attractive and natural.
In healthcare: Accurate color rendering is critical in medical facilities, for example, in assessing skin color or during surgical operations.
In photography and filmmaking: Professional photography and filmmaking use high CRI lights to achieve true-to-life and natural colors.

Measurement and History of CRI

In 1960, Nickerson proposed 18 color samples, of which 8 relatively low-saturation colors were used in the original CRI measurement methodology. These 8 color samples were evenly distributed across the color spectrum and formed the basis for calculating the general CRI (Ra). In 1974, the CIE expanded the CRI measurement methodology by adding 7 more color samples. These additional color samples provided a more comprehensive and accurate assessment of the color rendering capabilities of light sources. These 15 color samples provided a more extensive picture of the color rendering properties of light sources. In 1995, the CIE confirmed and standardized the use of these color samples in its official guidelines. This standard specified the methodology to ensure consistency and accuracy of measurements worldwide.

15 Standard Colors in the CRI Measurement Scale:

TCS01 (R1): Light greyish blue color used to assess the accuracy of bluish tones.
TCS02 (R2): Dark red color representing warm reddish tones.
TCS03 (R3): Yellowish green color used to evaluate the accuracy of greenish tones.
TCS04 (R4): Medium green color representing pure green tones.
TCS05 (R5): Turquoise color used to assess bluish green tones.
TCS06 (R6): Light blue color representing sky blue tones.
TCS07 (R7): Violet-red color used to evaluate the accuracy of reddish violet tones.
TCS08 (R8): Medium red color used to assess pure red tones.

Additional colors (R9 to R15) for more comprehensive evaluation:

TCS09 (R9): Deep red color often used in medical and food industries where accurate reproduction of red tones is critical.
TCS10 (R10): Saturated yellow color representing intense yellow tones.
TCS11 (R11): Saturated greenish-blue color used to assess the accuracy of bluish green tones.
TCS12 (R12): Saturated green color representing intense green tones.
TCS13 (R13): Saturated blue color used to assess deep blue tones.
TCS14 (R14): Saturated violet color representing intense violet tones.
TCS15 (R15): Flesh color used to assess the accuracy of skin tones, important in medical and cosmetic industries.

Summary

CRI is an important and widely used metric that helps assess the ability of light sources to reproduce colors naturally and accurately. Understanding and applying it can help make better lighting choices in homes, workplaces, and professional environments where color fidelity is crucial.

If you want to perform CRI measurement in your office or workspace, contact us and we will take care of it.

How to choose the right CRI lighting? - How does CRI affect our lives and which CRI value is best suited for specific environments, such as homes, offices, stores, and art galleries? Come to us for a consultation!