Buying Light Bulbs

     1. Light Bulb Shape and Base Shape: Light bulbs tend to be described by their shape name with terms such as globe, reflector or spiral. Light shapes are denoted with a letter-number-letter. The first letter indicates the bulb’s shape; the number is the bulb’s diameter at its widest part while the last letter designates bulb length. Base: There are two main types of light bulb bases: pin base and screw base. 

     2. Watts and Lumens: Watts measure the amount of energy required to light the light bulb, whereas lumens measure the amount of light produced. The more lumens produced by a light bulb, the brighter the light. 

    3. Color Rendering Index (CRI): Color rendering describes how a light source makes the color of an object appear to the human eye. The CRI is a scale from 0 to 100 percent indicating how accurate a "given" light source is at rendering color when compared to a "reference" light source; a typical comparison is to daylight. Light sources with a CRI of 85 to 90 are considered good at color rendering. Light sources with a CRI of 90 or higher are excellent at color rendering and should be used for tasks requiring the most accurate color discrimination. 

    4. Color Temperature: Color temperature is measured in degrees Kelvin (K). The color temperature of a light bulb describes how the light appears when an illuminated bulb is looked at directly by the human eye. Light bulbs that produce a yellowish white light may have a color temperature around 2700K, producing a “warm, cozy feeling.” As the color temperature increases, the yellowish color of the bulb decreases, and the white or “cooler” color increases. At 5000K or higher, the light color appears bluish white. 

 

See Home Lighting 101 for complete information HERE