Light Color and Color Rendering
True Colors do not exist.
People tend to judge colors under what they consider to be natural or true lighting conditions, often mistakenly using daylight for this purpose. but the colors seen under daylight on a Sunny day can be widely different to those seen on a day with overcast sky. For the spectral distribution of daylight is not constant, but is continually changing from hour to hour and from season to season. The correct thing to do, of course , is to assess the colors under the same type of lighting as that existing in the area where they will be finally seen. For example, an evening dress would be chosen under incandescent lighting, for this is the sort of lighting most likely to be employed at the evening function where it will be worn. Similarly, the color scheme for an office should be preferably be chosen under lighting identical to that which will later be installed there.
Spectral Distribution
The spectral distribution of the light determines the color characteristics. It is the spectral distribution of visible radiation which determines both the color impression and the color rendering capability of the light. These two characteristics are of vital importance with regard to lighting quality, as they largely determine the color impression that is received from the lighted scene.. New lamps each with its own characteristics appear on the market. As the choice becomes greater , so too does the difficulty of deciding on just the right lamp for a particular lighting situation.
Chromatic Adaptation
The state of chromatic adaptation of the observer (that is to say the condition of the eye in equilibrium with the totality of colors of the visual field) also plays an important role in the way colors are perceived. Strange as it may seem, the eye actually adapts to a given color and in the absence of clues to the contrary, tends to perceive that color as white.
A striking example of this may the case of ordinary incandescent lamp;looked at in the full light of day it appears rather yellow but the same lamps seen in the evening when daylight is no longer available as a reference, is decidedly white. Similarly, if various different colors of fluorescent lamps are installed in one and the same ceiling each will be clearly showing a distinct color tint, whereas all will be judged as being white when no direct comparison can be made.
Contrast effects in color
A colored surface is also influenced by its surroundings. Yellow flowers against a blue background appear more lively than when seen against a gray background. In general one cannot speak of right and wrong when referring to colors. Physically any color is right, however , the impression can be interpreted as more or less natural.
Relation between light color and preferred lighting level.
the choice of light source for a particular situation is also related to the lighting level employed. Warm colored light (low color temperature) is associated with warmth and is preferred at low lighting levels (as in sunset), while cool light (high color temperature) is experienced as being more natural when the lighting level is relatively high. this is why cool, bright light is so popular in tropics and sub tropics (where daylight levels are naturally high) whereas in more temperate climates precisely the opposite is true.
The color characteristics of lamps as specified in recommendations are generally expressed in terms of :
Lamps of Low Ra tend to be economical in energy consumption.
People tend to judge colors under what they consider to be natural or true lighting conditions, often mistakenly using daylight for this purpose. but the colors seen under daylight on a Sunny day can be widely different to those seen on a day with overcast sky. For the spectral distribution of daylight is not constant, but is continually changing from hour to hour and from season to season. The correct thing to do, of course , is to assess the colors under the same type of lighting as that existing in the area where they will be finally seen. For example, an evening dress would be chosen under incandescent lighting, for this is the sort of lighting most likely to be employed at the evening function where it will be worn. Similarly, the color scheme for an office should be preferably be chosen under lighting identical to that which will later be installed there.
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| Image Courtesy Philips |
Spectral Distribution
The spectral distribution of the light determines the color characteristics. It is the spectral distribution of visible radiation which determines both the color impression and the color rendering capability of the light. These two characteristics are of vital importance with regard to lighting quality, as they largely determine the color impression that is received from the lighted scene.. New lamps each with its own characteristics appear on the market. As the choice becomes greater , so too does the difficulty of deciding on just the right lamp for a particular lighting situation.
 |
| Courtesy Chinolite |
Chromatic Adaptation
The state of chromatic adaptation of the observer (that is to say the condition of the eye in equilibrium with the totality of colors of the visual field) also plays an important role in the way colors are perceived. Strange as it may seem, the eye actually adapts to a given color and in the absence of clues to the contrary, tends to perceive that color as white.
A striking example of this may the case of ordinary incandescent lamp;looked at in the full light of day it appears rather yellow but the same lamps seen in the evening when daylight is no longer available as a reference, is decidedly white. Similarly, if various different colors of fluorescent lamps are installed in one and the same ceiling each will be clearly showing a distinct color tint, whereas all will be judged as being white when no direct comparison can be made.
Contrast effects in color
A colored surface is also influenced by its surroundings. Yellow flowers against a blue background appear more lively than when seen against a gray background. In general one cannot speak of right and wrong when referring to colors. Physically any color is right, however , the impression can be interpreted as more or less natural.
Relation between light color and preferred lighting level.
the choice of light source for a particular situation is also related to the lighting level employed. Warm colored light (low color temperature) is associated with warmth and is preferred at low lighting levels (as in sunset), while cool light (high color temperature) is experienced as being more natural when the lighting level is relatively high. this is why cool, bright light is so popular in tropics and sub tropics (where daylight levels are naturally high) whereas in more temperate climates precisely the opposite is true.
The color characteristics of lamps as specified in recommendations are generally expressed in terms of :
- Color temperature in Kelvin- (K)
- Color rendering index CRI -(Ra)
Lamps of Low Ra tend to be economical in energy consumption.
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