Light Quality Issues With CFLs

It is certain that CFLs are an excellent alternative to incandescent bulbs when it comes to energy efficiency. However, when light quality becomes the issue, there is in effect no real substitute to incandescent bulbs. Most CFLs produce a cold blue light that many people find disturbing at best. This is subjective, you might say but the issue of light quality cannot be ignored as the consumer will always hesitate to adopt a technology that makes his daily life more somber.

The light quality of a lamp can be defined in terms of two indices: color temperature and color rendering. Color temperature refers to the colors produced by the light source. Color temperature is measured in degrees Kelvin. Color temperature can be classified into three types of color appearance: warm white (3000 K), cool white (4100K) and daylight/incandescent light (2750K). Even though lamps may have similar color appearances, their color rendering may be different. Color rendering refers to the appearance of colors under a particular light. A high color rendering index (CRI) means that colors look natural and vibrant while with a low CRI the colors may take on a different hue. A CRI of 100 means the colors would appear as they would be under normal daylight. A CRI of 1 indicates that color rendering is very poor.

Incandescent lamps have a very high color rendering (CRI 100). Under the color temperature of incandescent light, human skin looks the most natural. Because of this, incandescent light has become the standard by which all other lamps are measured. CFLs have significantly lower CRIs (variable according to the manufacturer). This implies that they distort the natural appearance of colors. CFL light is bluer, harsher and gloomier. Not an excellent lighting for a romantic dinner, for example. This is the main reason why they remained unpopular for so long until energy efficiency became an imperative for households. Even now, the quality of light given off by CFLs as perceived by the customer is lower than that of incandescent light.

Yet, manufacturers of CFLs are now technologically able to produce CFLs that emulate incandescent light effectively. This is done by having several layers of differently colored phosphors. However, having many layers of phosphors increases the cost considerably. Many manufacturers refrain from producing such CFLs for this reason.

There is gradually a mind shift on the part of the industry lately. A new study recently published online by Popular Mechanics compared 7 CFLs with a standard 75 watt incandescent lamp on such parameters as:

• Color temperature
• Watts consumption
• Subjective examination by individuals in a color-neutral room

The surprising discovery of this study is that the new CFLs scored better in the subjective examination than the incandescent lamp. This means that people now see better in a CFL environment than in an incandescent environment. The complete results of the study can be viewed at http://www.popularmechanics.com/

It is therefore interesting to note that CFLs are now more effectively emulating incandescent light, thus reconciling quality with energy efficiency.