Basic lighting effects for lighting
When designing and planning lighting, the three main elements of a lighting plan are:
- Base lighting to ensure the required illuminance
- Decorative lighting to decorate the space with brackets and chandeliers
- Spatial lighting to create the background of the space
These are the three main elements of a lighting plan. Base lighting is the functional brightness for the floor and desk surfaces, while decorative lighting is the selection of products such as chandeliers and brackets that match the image of the space when coordinating the space. In spatial lighting, it is not only important to select functional lighting that is effective for architectural lighting, but also to consider the conditions for fitting lighting fixtures such as "irradiation distance", "irradiation angle", "interior materials", and "surface finish" in order to make the most of the light distribution characteristics of the lighting fixtures. Spatial lighting varies depending on the individual site conditions, so we will explain the basic lighting effects. The expression of the space and the resulting impression also change depending on the material, so we hope that you will reflect this in the composition of the lighting space.
Types of reflected light
[Regular reflection]
Specular reflection is light that is reflected at the same angle on a perpendicular axis as the angle of incidence. A distinctive feature is that the reflected light can be clearly perceived in the direction of the incident light, but can be clearly perceived at other angles. For example, when light shines on hair-finished metal, the appearance changes depending on the angle from which it is viewed. This can be said to be a lighting effect that makes use of specular reflection at each angle.
[Diffuse reflection]
Diffuse reflection is light in which incident light is scattered in various directions on a reflective surface. The characteristic is that light is reflected at various angles, so the light can be clearly recognized from other angles. A typical example is indirect lighting. You can recognize the sense of brightness from various viewpoints. Another characteristic is that direct light is diffused through diffuse reflection, which reduces the glare of direct light and changes the light to be gentler on the eyes.
◎ Reflected light and color
Light is not monochromatic, but a collection of seven colors. For example, when light passes through a prism, it appears as seven colors like a rainbow: purple, indigo, blue, green, yellow, orange, and red.
In other words, light contains a variety of colors. The seven colors are also made up of light of different wavelengths. But what would it look like if you shined light on a red material? Light with wavelengths close to red is reflected, and light with wavelengths far from red is absorbed by the material as heat. This makes the red material look even redder. Even in supermarkets, there are lighting fixtures for meat, fresh fish, and prepared foods. In the sense of bringing out the color of the material. This is one example of the same effect.
Types of transmitted light
[Specularly transmitted light]
Transmission is the light that passes through an object. A material with high transmittance is 94% of acrylic resin. Light transmittance is the amount that indicates how much light is not attenuated when passing through a material. Light transmittance varies depending on the type and thickness of the material, the wavelength of light, and the angle of incidence. Generally, light is reflected or absorbed by the material when it passes through. When it passes through, it is transmitted as refracted light. Absorbed light is converted into heat.
[Diffuse transmitted light]
Diffuse transmission is light that is diffusely reflected within an object and passes through it. Typical examples are milky white materials such as acrylic and glass. When passing through a milky white material, about 48% of the light passes through at a thickness of 3 mm, which is nearly half. Also, the thicker the material, the lower the transmittance. For this reason, materials such as acrylic resin are often lightweight and thin, with high diffusion. Also, the thicker the milky white material, the higher the rate of heat conversion when passing through, which lowers the transmittance.
◎ Transmitted light and color
When light is shone on a colored glass object, such as stained glass, some light colors pass through. Other colors are absorbed by the object. For example, when light is passed through red glass, the light appears red because light close to red is transmitted and other light far from red is absorbed. Light that passes through a transparent object in this way is also called transmitted light.
[Surface emission]
Surface emission refers to emitting light from the entire light-emitting surface. Some lighting fixtures use fluorescent acrylic light guides and reflectors to diffuse the LED light. In architectural lighting, light is directed at a surface that receives light, such as a wall, and the diffused light is directed at a material that emits light, such as acrylic, to make it appear to be emitting light. It is common to see signs with light shining from behind the acrylic surface of a sign. In particular, you often see uneven lighting due to the color of the sign. This is a phenomenon in which uneven lighting occurs when the amount of light that penetrates is small due to the relationship between transmitted light and color.
[Prism illumination]
In architectural lighting, light is directed at a surface that receives light, such as a wall, and the light that is scattered is reflected by prisms made of acrylic or sheets, making it appear as if it is emitting light. It is often used in elevator lighting and as a light ceiling to reduce glare and diffuse light. Surface illumination by prisms has become less common in recent years. The reason for this is thought to be cleaning.
For reference information on the reflectance of different materials, please see the following link : "Iwasaki Electric Co., Ltd. Optical Properties of Materials"