Cree® TW Series LED Bulb – External FAQs

Cree® TW Series LED Bulb – External FAQs
1. What is Color Rendering Index?
Color reproduction is an important characteristic of any type of lighting, including LED lighting. Color
reproduction is typically measured using the Color Rendering Index (CRI). CRI is measured on a scale up
to 100. The higher the CRI, the more accurately you will see the actual colors of objects that the bulb
illuminates (i.e. reds will look red).
Daylight has the highest CRI (~100), with a 2700K incandescent bulb being relatively close, and
fluorescent lighting being much less accurate (CRI 70-85). Certain types of specialized lighting, such as
sodium lights (street lights with yellow orange colored light) exhibit a relatively low CRI (as low as about
CRI 20 – 30). The Cree TW Series LED bulb has a high CRI of 93, unmatched for LED bulbs, making colors
look the way they were intended.
2. Is there such a thing as good CRI and poor CRI light?
The higher the CRI of a bulb, the more accurately you will see the color of objects illuminated by its light.
According to ENERGY STAR®, a bulb with a CRI of 80 is the minimum acceptable for ENERGY STAR
qualification. According to this standard, anything below 80 could be considered poor CRI light. A light
bulb with a CRI of 80 is a excellent general use bulb for the home.
3. Isn’t 80 CRI good enough?
Yes it is - but good enough for what? For general illumination it is fine. But there are certain applications
where a higher CRI light might be preferred. In places where you want to accurately display the colors of
fabrics, woods, food, skin, you may want a high CRI light source to see the true and natural colors.
4. So then ANY 80 CRI bulb is good?
Not exactly, not all 80 CRI bulbs are the same. LEDs produce light with broad a color spectrum, like
natural light has, while CFLs have very narrow bands of color, forcing your brain to fill in the missing
color gaps. Many people find this disturbing without even knowing why. Both may have a similar CRI,
but in fact the CFL light is a much poorer quality of light.
5. Are there any other A19 LED bulbs that have as high a CRI as the TW Series
Currently, the limited offerings of A19 bulbs with greater than CRI 90 is small and these bulbs offer a
variety of compromises including higher price, shorter warranty, and non-optimal optical performance.
6. What is neodymium?
Neodymium is a naturally occurring element (#60 on the periodic table) that is added to the glass of the
Cree TW Series LED Bulb. The addition of this element gives a unique-looking blue/violet tint to the glass
bulb, and augments the LED light that passes through it and greatly increases the CRI of that light.
7. The Cree TW Series bulb achieves high CRI through spectral notching, what
does that mean?
The addition of neodymium in the glass of the bulb affects the LED light passing through the bulb to
create a “spectral notch”. A spectral notch is a portion of the color spectrum where the light is
attenuated thus forming a "notch" in the spectrum. By notching a portion of the yellow light, you get a
higher contrast between reds and greens which brings out the true colors of what is illuminated. What
remains is LED light that has a higher CRI.
8. Does the Cree TW Series LED Bulb meet the new California Energy
Commission (CEC) specification?
Yes, The Cree TW Series LED Bulbs are the first to meet the stringent requirements set for LED Bulbs by
the California Energy Commission in the Voluntary California Quality Light‐Emitting Diode (LED) Lamp
9. Is the Cree TW Series LED Bulb ENERGY STAR® qualified?
Not at this time. The Cree LED bulb is currently in the qualification process for earning ENERGY STAR
10. Is the Cree TW Series LED bulb dimmable?
Yes. The Cree TW Series LED bulbs are easily dimmable with most widely available standard
incandescent dimmers.
11. When will the Cree TW Series be available to purchase?
The Cree TW Series LED Bulb is available now online at and will be available this
fall at The Home Depot® stores in California.
© 2013 Cree, Inc. All rights reserved. Cree® and the Cree logo are registered trademarks, and
Filament Tower™ is a trademark, of Cree, Inc. The Home Depot® is a registered trademark of
Homer TLC, Inc. ENERGY STAR is a registered trademark of the U.S. Government.