Be careful with lighting
Here we have compiled points for improvement and caution regarding lighting effects, focusing on phenomena that have occurred around us or on-site, and matters that we have been consulted about. If there is anything that concerns you around you or on-site, we would like to update it from the perspective of lighting planning. Also, if there is anything that concerns you, we would appreciate it if site visitors would contact us by email. We would like to post content that will be of importance to all site visitors as a shared site. We appreciate your cooperation in running the site.
①: Selecting lighting fixtures for indirect lighting
The color and texture of the material that receives the light not only affect how the light appears, but also causes discomfort due to reflected glare (brightness caused by reflection). The indirect lighting shown here was installed by a construction company at the izakaya site as a retrofit. The lighting fixture installed was an FL20W daylight white direct-mount fixture. It is common for the lighting company to do this without considering the lighting distance or the surface it is illuminating, and to only focus on making the indirect lighting look bright. In the end, it was changed to a compact fixture with a warm white light. At sites like this, it is sometimes the case that lighting fixtures that are close by are installed without considering the conditions. In such cases, it is important to check the lighting distance and the material and color of the illuminating surface, and then make adjustments at an on-site meeting.
● The items to be checked include:
1. Installation location and installation method of the lighting fixture
2. Confirmation of the irradiation distance
3. Confirmation of the material (color and gloss) of the irradiated surface
4. Confirmation of the wiring route.
②: When using glareless downlights
One thing to be aware of when using glareless downlights is that they are difficult to sense the brightness of on the ceiling surface. Glareless downlights are lighting fixtures that were created by foreign-owned shops with the aim of reducing the glare on the ceiling surface and highlighting only the products. Westerners are extremely sensitive to glare, especially with light that is concentrated and distributed, which is why these lighting fixtures were created. However, Japanese people, especially older people, often feel that they are too dark. They are highly adaptable to younger people, but for older people, it is necessary to check the characteristics and brightness of the lighting fixture using installation photos and samples when planning lighting for homes, etc.
● Check items include:
1. Check the lighting fixture when it is turned on
2. Check the brightness directly below the fixture
3. Check the illuminance balance.
③: Reflectance of the object being irradiated
When using concentrated light, it is necessary to check whether there are any reflective materials or textures directly below the lighting fixture. As shown in the photo on the right, light from the floor, table, etc. can be reflected onto the ceiling surface due to regular reflection. In such cases, it will be necessary to attach a frost filter or, in the case of movable lighting fixtures such as universal downs, to adjust the angle to blur the reflected light. The optimal solution is to use furniture with a rough surface to blur the reflected light.
● Check items include:
1. Check the consistency between the furniture layout diagram and the lighting arrangement diagram
2. Check the finish of the furniture, floor materials,
etc.
④ Regarding the brightness of the sign surface
The basic plan was to shine light on the walls inside the curtain wall, then use internal lighting to make the curtain wall shine. However, due to a change in the plan on site, the plan was changed to lighting up the curtain wall and using reflections to make it shine. The original plan was to use a cutting sheet to shine light inside the curtain wall, but the light was reflected directly from the glass surface, making it impossible to focus the light in the center of the glass. When viewed from a distance, the brightness in the center is reduced, but you can see that the light from the upper lighting fixtures reaches the center when viewed from below the sign.
Measures to make the curtain wall shine in this way include:
① Fitting the lighting fixtures on the inside ⇒ Allowing maintenance to be done from the inside.
② Roughening the glass surface to allow light to be diffused and reflected ⇒ Cleaning the glass surface will need to be considered.
③ Using four spotlights to ensure a certain distance from the glass surface, and shining light on the top, bottom, and center. These are the measures that can be considered.
From afar
From nearby
⑤ Ensuring a sense of brightness
We often hear from people that they have secured the illuminance, but it doesn't feel bright. In particular, many people think that they can get the required illuminance but don't feel it is bright, so they want to increase the number of lights as a solution. First of all, we recommend shining light on walls, etc. The reason is that when we sense brightness in the line of sight, we perceive it as bright. Even if the required illuminance is secured, it is necessary to check how much illuminance or brightness is on the wall.
Check items include:
1. Check the illuminance and luminance on the wall
2. Check the range of brightness on the wall ⇒ Check the light distribution of wall lighting fixtures.
⑥ Lighting plans using bare light bulbs
In new or renovated residential lighting, LEDs and other bare bulbs may be used to ensure brightness. They may also be used as basic lighting in addition to hand lighting. One thing to note here is that if you plan based on illuminance standards, you will end up planning a significant number of lamps. This is because for general diffuse lighting, you will need about five times as many lamps as the ones shown on the right in the photo to ensure sufficient illuminance on the floor. When planning with general diffuse lighting, it is important to plan based on the luminance balance of the floor, walls, and ceiling, rather than on illuminance guidelines.
Check items include:
1. Check the color and brightness of the interior materials
2. Check the luminance balance of the floor, walls, and ceiling in the range of 5 to 12 cd/m2.
7. How to use color temperature
A common problem is the color temperature of light when a dining space and a kitchen space are adjacent. Practical light can look out of place in a space with a good atmosphere. If there is an extreme difference in color temperature between adjacent spaces, it can create an awkward feeling. The idea to avoid an extreme difference in color temperature is to avoid an awkward feeling. In that case, the key is to create a lighting environment in which the main dining space is the axis and the work space area has a higher color temperature, or to use light from fixtures with a light distribution angle of ∠30 or movable lighting fixtures so that the light does not hit the walls or fixtures.
Check items include:
1. Check the color temperature of the adjacent space
2. Check where light can be seen in the work space from the dining space *This depends on the situation on site, but there is no problem if the color temperature is the same.
3. Check the light distribution of lighting fixtures in the work space *In the work area, reflected glare can cause discomfort when working, so be careful about the light concentration and the position of the fixtures.
⑧ Mitigating reflections
In street-facing offices and shops, we often receive consultations about the effect of reflections during the day, which makes it difficult to see the interior or business atmosphere. In particular, when planning, we hear that the brightness of the floor and desk surfaces is ensured, but the interior is unclear, and even in the office, the daytime feels darker than at night due to the influence of lighting, and there is an overall feeling of darkness. In such cases, we will give advice on the surface brightness of the walls and ceiling. Not only does the reflection phenomenon cause a sense of darkness, but the feeling of darkness indoors also makes you feel visually tired, and from a safety and health perspective, the feeling of darkness creates psychological anxiety. In addition to being conscious of the appearance from the outside, it is important to have a sense of brightness on the walls and ceiling as part of the visual environment. Since most work is done on PCs, which mainly revolve around screen brightness, the indoor lighting environment is even more important.
The check items include:
1. Confirm the perceived brightness of the walls and ceiling surfaces.
2. Confirm the reflectance and transmittance of the exterior glass material.
3. Confirm the purpose and work content of each part.
4. Confirm the illuminance and brightness balance of the floors, walls and ceiling surfaces in the office when the daylight sensor is activated. *If a daylight sensor is used.
5. Confirm the brightness from outside by simulating the illuminance during the day.
When there is no sense of brightness in the room
When there is a sense of brightness in the room