Use of Light and Color

Color is a sensory effect produced in the human eye and visual system by light emitted from or reflected off surfaces of objects. For an object to be perceived as colored, light with specific characteristics must reach the eye from that object. Therefore, color perception depends not only on the physical structure of the object but also on the properties of the light and the observer’s biological system.

Light is a form of energy carried by photons and characterized by wave properties within a specific range of the electromagnetic spectrum. The human eye can perceive only a limited portion of this spectrum, known as visible light. Ultraviolet and infrared rays outside the visible range cannot be directly detected by the human visual system. This distinction highlights the difference between the physical reality of light and the perception of color.

The relationship between light and color holds fundamental importance across various disciplines. In physics, processes such as refraction, reflection, and absorption of light explain the emergence of colors. In art and design, color is evaluated as an aesthetic and expressive tool. In technology and engineering, color perception plays a central role in the development of imaging systems, display technologies, and optical devices.

The formation of color perception is a multidimensional process shaped by the wavelength and intensity of light, the way object surfaces absorb or reflect light, the responses of photoreceptor cells in the retina, and the brain’s method of processing visual data. Additionally, an individual’s psychological state, cultural context, and environmental conditions can influence how colors are perceived. Thus, color is not merely a physical phenomenon but is regarded as a complex phenomenon with biological, psychological, and cultural dimensions.

Nature of Light and Formation of Colors

Light represents only a small portion of the broad range of wavelengths known as the electromagnetic spectrum. The electromagnetic spectrum encompasses a vast variety of frequencies and wavelengths, extending from radio waves to gamma rays. The human eye, however, can perceive only a narrow segment of this spectrum, approximately between 380 and 760 nanometers (nm). This range is called “visible light.”

Each wavelength within the visible light spectrum is interpreted by the human visual system as a different color. Shorter wavelengths correspond to the violet and blue ends of the spectrum, while increasing wavelengths are perceived sequentially as green, yellow, orange, and finally red at the longest wavelengths. This orderly sequence of colors is most prominently observed in natural phenomena such as rainbows or in prism experiments.

White light is not a single color but a combination of all wavelengths within the visible spectrum. The color an object appears to be is determined by its interaction with incident light. For example, an object that appears blue under white light reflects only the blue wavelength among all the wavelengths composing white light and absorbs the others. The reflected blue light reaching our eyes causes the object to be perceived as blue.

If an object reflects all incident wavelengths, it appears white; if it absorbs all wavelengths, it appears black. This demonstrates that color perception depends not only on the object’s structure but also on the characteristics of the light source illuminating it. For instance, a blue object illuminated solely by red light will absorb the red light and have no blue light to reflect, and thus will be perceived as black.

This fundamental physical process underlying color formation has extensive applications both scientifically and practically. In physics, the properties of light reflection, refraction, and absorption form the basis of optics. In art and design, light and color are regarded as tools of expression and aesthetics. In technology and engineering, these processes are applied in numerous fields, from display technologies and camera systems to lighting engineering and image processing methods.

Mixing Light Colors (Additive Color Mixing)

The process of mixing light colors is based on a different physical principle than the mixing of pigments or paints. This phenomenon is known as “additive color mixing.” Additive mixing relies on the combination of three primary light colors that the human eye can perceive: red, green, and blue. These three primary components are commonly referred to as the RGB system.

In additive mixing, all visible colors can be produced by combining the three primary colors in varying proportions. For example, the combination of red and green produces yellow, red and blue produce magenta, and green and blue produce cyan. When these three colors are combined at equal intensity, they produce white light. This property is directly related to the spectral composition inherent in the nature of light.

Additive color mixing plays a central role in technological devices. Systems that generate their own light, such as television screens, computer monitors, smartphone displays, and projectors, operate on this principle. These devices control red, green, and blue pixels at varying brightness levels to produce millions of different colors. As a result, the eye perceives continuously changing color tones, enabling the creation of rich visual content.

Color Temperature (Kelvin Value)

Color temperature is a measure used to describe the perceived color tone of a light source and is expressed in Kelvin (K). This concept is based on the principle that a metal object emits light of different colors at different temperatures as it is heated. As temperature increases, the emitted light shifts from reddish to yellow, then to white, and finally to bluish tones.

General classification is as follows:

• Warm Light (<3300 K): Produces yellowish and reddish tones in the range of 2700–3000 K, similar to candlelight or sunset light. Such lights are often preferred to create a relaxing and intimate atmosphere.
• Natural Light (3300–5000 K): Offers a balanced tone close to natural daylight at midday. Widely used in residential and office lighting.
• Daylight/Cool Light (>5000 K): Found in the range of 5000–6500 K, this light has a bluish-white appearance. It is preferred in work areas because it enhances alertness and concentration.

The choice of color temperature affects not only the quality of illumination in a space but also the psychological perception of the environment. Lower Kelvin values create a warmer and more tranquil atmosphere, while higher Kelvin values produce a more dynamic and stimulating environment. Additionally, color temperature can alter the perception of colors on surfaces. For example, the same object may appear in different tones under 2700 K warm light compared to 6500 K cool light. Therefore, color temperature is a carefully considered element in many fields, from architectural lighting to industrial design and visual arts.

Light and Color in Lighting Design

Lighting design is a fundamental element that directly influences the functionality, aesthetic unity, and user experience of a space. Conscious use of light and color can shape perceptions of spatial dimensions, atmosphere, users’ moods, and behaviors within the environment. Therefore, lighting design aims not only to meet visual needs but also to define the identity of the space.

Use of Natural and Artificial Light

Natural light is one of the most effective sources for creating brightness and openness in spaces. The quality of daylight varies according to the time of day, season, weather conditions, and the geographic orientation of the space. For example, rooms facing east receive warmer, yellower tones in the morning, while rooms facing north receive cooler, more neutral, and shadowed light throughout the day. These variations directly affect how colors are perceived in interior design.

Artificial lighting is employed either when natural light is insufficient or to create specific atmospheres. An effective lighting design typically integrates three fundamental types of lighting in layered form:

• Ambient Lighting: The basic illumination that evenly spreads throughout the space. Chandeliers, ceiling lights, or recessed spotlights serve this purpose.
• Task Lighting: Functional lighting focused on specific activities. Reading lamps, kitchen counter spots, or desk lamps fall into this category.
• Accent Lighting: Decorative lighting used to highlight specific elements of the space. Spotlights on artworks, architectural details, or display cases serve this purpose.

Balanced application of these three types ensures that the space is perceived as both functional and aesthetically harmonious.

Technical Factors Affecting Color Perception

The technical properties of artificial light sources significantly alter how colors are perceived within a space. Two additional parameters, alongside color temperature (CCT), are crucial: the Color Rendering Index (CRI) and the Luminance Reflectance Value (LRV).

• Color Rendering Index (CRI): Measures how accurately a light source reveals the colors of illuminated objects compared to their natural appearance under daylight. The scale ranges from 0 to 100, with 100 representing the highest fidelity, equivalent to natural daylight. Light sources with low CRI values may render object colors as dull, artificial, or inaccurate. Therefore, high-CRI light sources are preferred in environments where color accuracy is critical, such as art galleries, textile stores, or kitchens.
• Luminance Reflectance Value (LRV): Measures the percentage of light reflected by a surface. A value of 0 represents pure black, and 100 represents pure white. Light-colored surfaces with high LRV reflect more light, making a space appear brighter than it physically is, while dark-colored surfaces with low LRV absorb light and create a dimmer environment. This characteristic is also significant in terms of lighting costs and energy efficiency.

Considering light and color together in lighting design does not merely produce aesthetic outcomes; it also determines the psychological impact of the space, energy consumption, and usage efficiency. Therefore, successful lighting design integrates physical, visual, and psychological elements in a balanced manner.

Perception of Width and Openness in Interior Spaces

The use of light and color significantly influences the perception of a space’s dimensions and volume. Especially in small spaces or those with limited natural light, appropriate color and lighting strategies can create a more expansive, open, and inviting atmosphere.

Light and neutral colors—white, cream, beige, and light gray tones—are the most commonly preferred options in interior spaces. Due to their high light-reflecting properties, these colors blur spatial boundaries and create a visually expansive effect. Using light colors on walls and ceilings, particularly in combination with natural light, enhances the perception of brightness. Painting the ceiling one tone lighter than the walls reinforces the perception of height. Similarly, selecting furniture in tones that harmonize with the walls contributes to visual unity and enhances the sense of openness.

Strategic use of mirrors is a direct and effective method for increasing perceived space. Large mirrors placed opposite windows reflect natural light, raising the room’s brightness and adding depth. In artificial lighting, directing fixtures upward (uplighting) makes the ceiling appear higher. Additionally, using furniture that is elevated off the floor and has a lightweight, functional appearance increases the visibility of the floor area, supporting the feeling of openness.

These techniques not only serve aesthetic purposes but also influence users’ psychological perception. An open environment can evoke feelings of comfort, calmness, and prolonged well-being in individuals.

Light and Color in Photography

Photography is an art fundamentally based on capturing light and organizing color. The direction, intensity, and color of light are essential elements that determine a photograph’s atmosphere, texture, and narrative power. Therefore, photographers consciously and innovatively manipulate light sources to create visual effects.

Natural light is one of the most important tools in photography. Different times of day offer varying conditions in terms of light warmth and softness. For example, the short periods around sunrise and sunset are known as the “golden hour.” During these times, light arrives at low angles, has a yellowish-reddish tone, and produces soft shadows. These characteristics create a warm and romantic atmosphere in portrait and landscape photography. The brief period following sunset is known as the “blue hour”; during this time, light takes on cooler, bluish tones, contrasts become more pronounced, and it provides a powerful visual effect, particularly for cityscapes.

Artificial light sources also have wide applications in photography. Studio flashes, continuous lighting systems, and color filters give photographers complete control over composition. The white balance setting on cameras is used to balance differences in color temperature, playing a critical role in ensuring colors appear natural under varying lighting conditions.

Understanding color theory is also important in photography. Color harmonies (complementary, analogous, triadic) and contrast relationships determine the visual appeal and aesthetic unity of a composition. For instance, complementary colors create strong contrast, while analogous colors produce a harmonious and soft atmosphere. Thus, light and color become not merely tools for recording images but also expressive instruments that guide narrative power.