Difference Between a Full Spectrum Halogen & an Incandescent Light

Full spectrum halogen light bulbs burn brighter, whiter and hotter and last considerably longer than common incandescent light bulbs. "Full spectrum" lighting ratings indicate how close the light that the bulb emits resembles natural sunlight in color and intensity.

Incandescent Light Bulbs

An incandescent light bulb is a glass tube filled with gas, with a wire filament inside it. When the light bulb is illuminated with electricity, the filament becomes hot and gives off light. As the filament burns, the byproducts evaporate off it and deposit on the inside of the glass tube. When the filament has burned down to a certain point, it either breaks or simply disappears, and the light bulb burns out.

Halogen Light Bulbs

A halogen light bulb is also an incandescent light, but the gas in the tube is halogen and the filament is made of tungsten. Again, when the light is on, the filament gets hot and begins to burn, but the halogen gas captures the evaporating tungsten and deposits it back on the filament. Thus a halogen light bulb will last quite a lot longer than the average incandescent bulb.

Quality of Light

Besides a longer lifespan, a halogen light bulb burns with a clear, bright white light that emits considerable heat. (In fact, some appliance manufacturers use halogen bulbs as the heat source in small space heaters and even cooktops.) Not only do they burn cooler, incandescent bulbs also give off light that is markedly more yellow than natural light. If you look at a work of art or color pictures in a book or magazine under incandescent light, the color will appear to be much yellower than it will under natural light.

Full Spectrum Lighting Ratings

The term "full spectrum lighting" does not have a fixed definition, so reputable manufacturers and vendors of lighting products have taken it upon themselves to establish standards for the designation. Two indexes, the C.R.I. (color rendering index) rating and the color temperature rating, have become the most commonly used measures of how closely a light bulb will render full spectrum light.
The C.R.I. rating ranges from 1 to 100. The closer the bulb's rating to 100, the closer the light it casts will be to natural sunlight. The color temperature rating refers to the light spectrum of the light that the bulb emits. The rating is measured in degrees Kelvin, and a color temperature rating of 5000 or better indicates that the bulb is giving off a broad spectrum of light.

Incandescent Full Spectrum Light Bulbs

Some vendors sell incandescent light bulbs called "full spectrum" bulbs, but these bulbs have no C.R.I. or color temperature rating. The designation in this case simply means that the light they emit is less yellow than that of regular incandescent bulbs.