Visual comfort
Satisfaction with lighting is one component of overall environmental satisfaction in residences. Good lighting can create a sense of comfort. Lighting conditions that cause visual discomfort involve either the presence of an excessive range of luminance in the field of view, which results or in glare the cyclic variation in light output at an unacceptable amplitude, which is referred as flicker. Task performance, mood and atmosphere, health and safety can be negatively affected by glare and flicker. Exposure to luminance which is excessively high in relation to the state of ada may lead to disability glare or discomfort glare. Glare is a major concern in residential spaces where people spend a lot of time. Disability glare causes a reduction in visual capabilities. Discomfort glare creates a sensation between "just comfortable" and extremely comfortable sensation may be irritation or pain. Flicker refers to visible or invisible periodic or irregular changes in source l uminance. Flicker may result in fatigue, eyestrain and blurred vision. In some populations, flicker can trigger symptoms such as headaches, migraine and photosensitive epilepsy.
Mood and atmosphere
Lighting can be used to create welcoming, emotionally supportive environments. The color appearance of a light source is often referred to as being "warm", "neutral", or "cool". Warm white light has a reddish tone, while cool white light appears bluish. The tone of white light can be characterized using a metric called correlated color temperature (CCT). The lower the CCT, the warmer the cast of white light; the higher the CCT, the cooler the light source appears. The CCT of warm white light is usually within the range of 2700 K to 3300 K. The color appearance of a light source has a direct impact on many aspects of human experience, including relaxation, stimulation, concentration, alertness, and preference. White light with a CCT above 4100 K is referred to have a "cool white" appearance. Heavy laden with red and orange wavelengths, warm white light imparts a feeling of comfort, comfort and relaxation to a space. Warm white light sources are therefore more commonly used inside residen Tial applications where an inviting, intimate and cozy atmosphere needs to be created. Cool white light, on the other hand, makes people feel cold and a room appear more spacious. Because it discourages relaxation and deprives a space of warmth and intimacy, cool white light is generally a rare choice for residential settings.
