{{unreferenced, date=December 2009 Amber shift is a phenomenon of

incandescent lamps An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxidat ...

in which the perceived warmth (or

colour temperature Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...

) of the light sources changes as larger amounts of

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...

flow through it.

Basic example

This can best be seen with domestic lighting which is controlled with

dimmer A dimmer is a device connected to a light fixture and used to lower the brightness of the lighting, light. By changing the voltage waveform applied to the lamp, it is possible to lower the luminous intensity, intensity of the light output. Alt ...

s. When the dimmer is turned down the light being produced also appears to be more of a warm, amber colour. Whereas when the light level is increased the light becomes more white.

Uses

This characteristic of incandescent lighting can be used for various practical applications where a different colour temperature of light is required.

Art exhibitions

Often an artist will want to show his or her work in high colour temperature light. The reason for this is because a higher colour temperature will give a more accurate representation of colours in paintings, photos, etc. Some artists may use amber shift properties to accentuate the warmth of a piece.

Social and dining

Often restaurants, bars and other social gathering places will dim lighting to maximise amber shift. The reason for this is that the warmer (amber shifted) light shows

skin tone Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics (inherited from one's biological parents and or individu ...

s in a more attractive manner. Some interior designers also feel that warmed light gives a more intimate feel.

Counteracting amber shift

In cases where incandescent light is in use, but a high colour temperature is required, a technique called "colour temperature correction" may be used. This involves placing a "CT" light filter in front of a light source. To the naked eye this type of filter appears blue, but when put in front of an amber shifted light source it counteracts the dominant amber colours to produce a more white light through a process known as

subtractive mixing Subtractive color or subtractive color mixing predicts the spectral power distribution of light after it passes through successive layers of partially absorbing media. This idealized model is the essential principle of how dyes and inks are used ...

. Color space Incandescent light bulbs