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Writer's pictureEmiliano Terán

The Mystery of Metamerism: How Light Affects Our Perception of Color



Introduction


Have you ever wondered why the colors of your clothes seem to change when you are in different environments with different light sources? This phenomenon, known as metamerism, is defined as the color match of two objects under one lighting condition, but a perceptible difference in color when viewed under another lighting condition. Metamerism affects our perception of color in our daily lives and has important implications in various industries. This essay will explore metamerism, its relationship with optics and lighting, and its impact on our daily lives and on different industrial sectors.


I. Light and colors


The human visual system consists of two main types of photoreceptors in the retina: rods and cones. The cones are responsible for color perception and are more sensitive to bright light, while the rods allow us to see in low light but do not distinguish colors. When light falls on these photoreceptors, a transduction process occurs that converts light energy into electrical impulses that the brain interprets as color.


To better understand how metamerism affects our perception of color, we must first understand the relationship between light and colors. The visible light spectrum spans a range of wavelengths that the human eye can perceive, approximately 400 to 700 nanometers. The shortest wavelengths, around 400 nm, correspond to the most energetic photons and are perceived as blue or violet colors. On the other hand, the longer wavelengths, around 700 nm, correspond to less energetic photons and are perceived as red colors. Differences in the energy of these photons can have an impact on ocular tissues, such as the retina, cornea, or lens, and affect their function over time.


II. Radiometric and Photometric Quantities of Light and Reflective Surfaces


When discussing metamerism, it is important to consider the radiometric and photometric quantities of light and reflective surfaces. Radiance and irradiance are two important quantities in optics and lighting that describe how light interacts with surfaces. Radiance is the amount of energy that a surface emits, reflects, or transmits per unit area and solid angle, while irradiance is the amount of energy incident on a surface per unit area.


These quantities depend on both the characteristics of the surface and the light source. For example, a rough surface will scatter light differently than a smooth surface, which will affect how we perceive its color. Similarly, different lighting sources can have different spectrums of light and therefore affect how colors are reflected from a surface. III. Metamerism in Industry


Now that we've explored the relationship between light, color, and radiometric and photometric quantities, we can look at how metamerism affects different industries.


In the public lighting industry, it is essential to develop light sources that allow consistency in the perception of color in different environments and conditions. Lighting designers seek to create lamps that reproduce colors accurately and consistently, regardless of whether they are used indoors or outdoors. In addition, they strive to develop lighting solutions that do not negatively affect people's health and sleep, such as lamps that emit less blue light or that automatically adjust to the needs of the environment and users.


Metamerism also represents a challenge in the paint industry, since the perception of the color of painted surfaces can vary depending on the type of lighting in the environment. For example, a paint color may appear different in sunlight compared to artificial light from an LED or fluorescent light bulb. To address this issue, paint manufacturers are working on formulating pigments and blends that allow for a more stable and consistent perception of color under different lighting conditions.


In addition, research in this area is also focused on the development of color measurement and assessment methods that can predict and assess metamerism in different environments. This allows design and architectural professionals to select paints and materials that offer the best color consistency based on project-specific lighting conditions.


Final remarks


To conclude, metamerism is a complex phenomenon that affects our perception of color in different environments and lighting conditions. Our visual system is sensitive to various forms of radiation, both visible and non-visible, and short-wavelength light, such as blue light, can have negative consequences on our health and circadian cycle.


The lighting industry and the paint industry face specific challenges in relation to metamerism. Both industries are working on the development of solutions that allow maintaining a consistent color perception and, at the same time, minimizing the negative impact on people's health and sleep.


Advances in the research and development of lighting and pigment technologies seek to address the issues of metamerism and human health. These efforts include the creation of lamps with a low impact on the circadian cycle and the development of paints and materials with a more stable perception of color in different lighting conditions.


Ultimately, it is essential to continue researching and developing innovative solutions in optics and lighting to improve people's quality of life and ensure that the spaces in which we live and work are comfortable, healthy, and visually appealing. Referencias


1. Foster, D. H. (2011). Color constancy. Vision Research, 51(7), 674-700.

2. Tosini, G., Ferguson, I., & Tsubota, K. (2016). Effects of blue light on the circadian system and eye physiology. Molecular Vision, 22, 61-72.

3. Teran, E., Yee-Rendon, C. M., Ortega-Salazar, J., De Gracia, P., Garcia-Romo, E., & Woods, R. L. (2020). Evaluation of two strategies for alleviating the impact on the circadian cycle of smartphone screens. Optometry and Vision Science, 97(3), 207-217.




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