Lighting For Your Home Or Cottage : Selecting The Best Colour Lamp

Life on the waterfront in Muskoka / Lake Of Bays is all about the colours. Choosing the right view is just as important as choosing the right colour of light inside your Muskoka / Lake Of Bays luxury cottage. It’s all about the blub!

When talking about white light sources (or about white paint) we use the descriptions “warm” and “cool.” White light with a yellowish tinge, reminiscent of candlelight and fireplaces, is called “warm white”. Incandescent lamps produce a warm white color. Bluish white, reminiscent of moonlight on cold snow, is considered “cool white”. Fluorescent lamps can produce warm white or cool white, or anywhere in-between, depending on the mix of phosphors used.

CORRELATED COLOR TEMPERATURE (CCT)

Correlated Color Temperature is a way of describing the degree of “yellowness” or “blueness” of a white light source. We relate the light source to the color of a hypothetical piece of hot metal. A piece of metal or tungsten as it is heated, will progressively change color in the sequence shown below:

Cherry Red | Bright Red | Orange | Yellow | Yellowish White | White | Bluish White

When we say a lamp has a color temperature of 2700K – typical of incandescent lighting – it simply means that a piece of metal heated to a temperature of 2700 kelvins (which is about 3000ºC or 5400ºF) would mimic the color of the lamp. Such a source would be yellowish-white. In contrast, the color of a lamp at 6000K – typical of daylight entering through a window on a sunny day – can be mimicked by doubling the temperature of the hot metal piece to 6000 kelvins. This is significantly bluer or “cooler” than the light of incandescent lamps. Note that the higher CCT refers to sources described as “cooler”.

Generally, 4000K and above is considered “cool white” 3200K and below is “warm white” and 3500K is “neutral white”.

Muskoka / Lake Of Bays BETTER COLOR RENDERING FOR BETTER APPEARANCE

There is no such thing as the “true” color of any material; the perceived color is a function of the light under which the material is viewed. However, we can make a general statement: the higher the Color Rendering Index (CRI) of a light source (also denoted by Ra)the better – and more natural – colors appear under the light source.

In measuring CRI, scientists compare how eight specific colors appear under the source to how these same colors appear under a reference source. However, there are two reference sources: incandescent lighting is the reference for warm color lamps and daylight is the reference for cool color lamps. In this system, both incandescent lamps and daylight are considered to have “perfect” CRI’s of nearly 100 even though, as we know, materials appear quite different when viewed under these light sources. These two sources are very different in color temperature (see below) although both have CRI’s close to 100. CRI is, therefore, meaningful in comparing lamps that are close in color temperature.

CRI is not a perfect measure, but it is still useful as an indicator of the quality of light from a source.

Typical color indicators
for various lamps
Correlated Color
Temperature
CRI
INCANDESCENT LAMPS
Typical
2500-2800K
97-100
HALOGEN LAMPS

Typical
2800-3000K
97-100
FLUORESCENT LAMPS (ordered by CCT)
C75 “Chroma Series”
7500K
90+
SPX65 (865)
6500K
80+
SP65 (765)
6500K
70+
C50 “Chroma Series”
5000K
90+
SPX50 (850)
5000K
80+
SP50 (750)
5000K
70+
SPX41 (841)
4100K
80+
SP41 (741)
4100K
70+
Cool white
4100K
62
SPX35 (835)
3500K
80+
SP35 (735)
3500K
70+
SPX30 (830)
3000K
80+
SP30 (730)
3000K
70+
Warm white
3000K
50
CovRfresh
2750K
87
SPX27 (827)
2700K
80+
Note: Some 4’ T8 “SP” lamps, including reduced wattage types, may have a CRI >80.
HIGH PRESSURE SODIUM LAMPS
Lucalox
1900-2100K
22
Delux Lucalox
2200K
65
METAL HALIDE LAMPS
Standard and PulseArc MVR Multi-Vapor
3000-4300K
65-75
MXR Multi-Vapor
3200-3500K
65-70
Arcstream
3000-6000K
75-90
Multi-Vapor ChromaFit
4000-4500K
65-70
CERAMIC METAL HALIDE LAMPS
CMH
3000-4200K
80-93
CMH ChromaFit
3000K
85

SPECTRAL OUTPUT OF LAMPS

While CCT and CRI are useful measures to indicate the color of a light source, the “true and complete” information about the source is contained in the spectral output curve. This curve tells us how much energy the lamp is emitting in each region of the spectrum. The incandescent lamp spectrum, for example, shows very little blue, consequently we might expect navy blue materials to appear almost black under this spectrum.

WHAT IS THE “RIGHT COLOR” FOR THIS APPLICATION?

People have preferences and the “right” color temperature is usually a subjective choice. An environment with “warm” color – reds, yellows and browns – will generally look more appealing and natural under warm lamps while “cool” colors – blues, greens and grays- will look more pleasing under cool lamps. However, this rule is sometimes broken to achieve a different atmosphere. Another notion to remember is that indoor spaces lit to low light levels typically look better under warm lamps while high light levels typically are tolerated better with cool lighting. In spaces where daylight is utilized, lamps with cooler color temperatures will integrate well with the higher color temperature of the daylight.

Once you have picked the lamp type and the “right” color temperature, whatever that is, it is best to go with the highest CRI lamp available in that family. Since electricity constitutes the major portion of expense of a lighting system over its life, choosing the highest quality light source makes the best use of the electricity consumed.