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Color rendering properties of interior lighting influenced by a switchable window
Marta Klanjsek Gunde1, Ursa Opara Krasovec, Werner J Platzer
1National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
Summary
Switchable windows alter daylight color rendering. New methods show color shifts, revealing distortions in object appearance at higher window coloration levels, impacting building aesthetics.
Area of Science:
- Building Science
- Optical Engineering
- Color Science
Background:
- Modern buildings increasingly utilize switchable windows for dynamic control of daylight.
- Gasochromic and electrochromic technologies offer variable light transmittance.
- The impact of these windows on the color rendering of transmitted daylight is not fully understood.
Purpose of the Study:
- To investigate how variable transmittance in switchable windows affects the color rendering properties of daylight.
- To evaluate the suitability of traditional color metrics and explore alternative methods for characterizing filtered light.
- To analyze the color shifts experienced by various objects under different window states.
Main Methods:
- Comparative analysis of gasochromic and electrochromic switchable windows.
- Measurement of daylight transmittance and color properties.
- Application of color shifts (deltaE) in the CIELAB color space to assess color changes.
- Evaluation of color rendering indices and correlated color temperature limitations.
Main Results:
- Correlated color temperature and color rendering indices are insufficient for accurately describing the color properties of light filtered through switchable windows.
- Color shifts (deltaE) provide more reliable results, showing consistent directional movement of surface colors in CIELAB space as transmittance varies.
- The direction and magnitude of color shifts differ among various test colors.
- Significant distortions in the appearance of colored objects occur at higher coloration states of the switchable windows.
Conclusions:
- Traditional color metrics are inadequate for characterizing the color rendering of switchable windows.
- Color shift analysis (deltaE) offers a more robust method for evaluating the impact of switchable windows on perceived colors.
- The visual appearance of colored objects can be substantially altered by switchable windows, particularly at high levels of coloration, necessitating careful consideration in architectural design.