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Color Shift

The CRI and CQS are both initial measurements of color rendition. Color shift is a term that describes
the change in the color rendition of a light source over time. This element is sorely missing from the
color requirements and it is left to the consumer to bear in mind.

The HID technology is long-known for its
notorious shift in color and very few consumers
remain unaware of this. (See Figure 6).

For decades, the fluorescent technology has
been superior to HID in color shift. Yet, while
pink and green hues manifest as the fluorescent
bulb matures, data pertaining to how much
color shift is exhibited is up to the manufacturer
to provide. As it is not in their best interest, the
data is virtually non-existent.

Figure 6. Example of Color Shift.

In the solid state technology, color shift is measured as a part of IES LM-80 testing, performed by all of
the reputable LED manufacturers (Figure 7).

Figure 7. Color Shift Data Required in IES LM-80

Competitive Analysis, Color Rendering in White Light Page 6