Lighting for Reading
The Different Types of LightThere are a number of different types of light, each with its own characteristics. When you go to the store to purchase a new lightbulb, it’s helpful to pay attention to three terms that you can find on every lightbulb box:
- Lumens: the amount of light that a lightbulb produces. The higher the lumen number, the more light the bulb will produce.
- Wattage: the amount of electricity a lightbulb uses. The higher the wattage number, the more electricity the bulb will use.
- Kelvin or K rating: a measure of “color temperature.” A Kelvin or K rating of 2,700 produces a warm, or yellowish, light; a K rating of 4,500 produces a white light that is closest to true daylight; and a K rating of 5,000 or above produces a cool or “bluish” light.
- For most people with low vision, a Kelvin rating of under 5,000 is usually recommended. This is partly because there will not be any blue light or ultraviolet if a lamp is under 5,000 K. Also, the lamp will probably be better contrast if it is under 5,000 K.
- The most important terms for people with low vision are lumens and Kelvin rating.
Sunlight/Natural LightAlthough natural sunlight is ideal for most everyday tasks, it can also present problems. Sunlight is not consistent throughout the day, and it can create glare spots and potentially dangerous shadowy areas in your home.
Incandescent Light (Basic Light Bulbs)Incandescent light emphasizes the red/yellow end of the visible light spectrum, which is closer to natural sunlight. The light from an incandescent light bulb is also very concentrated. That makes it best for “spot” illumination on close work, such as reading, sewing, and crafts. It is not recommended for overall room lighting, since, like sunlight, it tends to create glare spots and shadowy areas. Please note: At the end of 2014, the United States phased out production of all incandescent bulbs. Until supplies run out, these bulbs will remain on store shelves alongside the energy-saving alternatives that are replacing them.
Fluorescent Light and Compact Fluorescent Lamps (CFLs)Fluorescent light and CFLs produce less heat, use less energy, and are more cost-effective than incandescent bulbs. Fluorescents are usually recommended for overall room lighting because they don’t create glare spots and shadows. A CFL is a compact version of a fluorescent tube that is curved or folded to fit into the space of a standard bulb. Look for CFLs with a K rating of around 4,200 but under 5,000. CFLs have some drawbacks, however:
- CFLs take time to warm up and achieve full brightness.
- Some models can’t be used with a dimmer switch.
- Because they contain a small amount of mercury, CFLs must be recycled at a hazardous materials facility. Also, it’s not easy to avoid mercury contamination when cleaning up broken CFLs.
Light-Emitting Diodes (LEDs)LED bulbs produce minimal heat, are very energy-efficient, and achieve full brightness instantaneously. The energy-producing part of the light, the diode, is encased in a hard plastic cover that looks like a standard bulb and will not break easily. LED bulbs do not contain mercury, have a life expectancy of 50,000 hours, and work best for concentrated lighting on close work in a flexible-arm lamp with a shade that directs the light downward. They are not recommended for overall room lighting. Look for LEDs with a K rating of around 4,200 but under 5,000.
Halogen LightSome people prefer halogen light because it is brighter, “whiter,” and very concentrated. It is used in lamps, track lighting, and ceiling fixtures, and it is also available in adjustable gooseneck and flex-arm lamps. There are some disadvantages to halogen light, however:
- Since it is hotter and more focused than other types of light, it is not recommended for prolonged close work.
- When used in a reading lamp, the bulb must be shielded by a piece of protective Plexiglas or durable plastic.
- It produces intense heat and can cause fire and severe burns if used incorrectly. Always follow the manufacturer’s safety precautions when using halogen lighting fixtures.