White or Black: either way, it blocks 87%+ of near-infrared rays
CORE SHIELD® innerwear comes in White and Black. People often say black is better for UV protection—but what about near-infrared rays? Here are the numbers we measured for both colors, as they are.
The same fabric, measured in two colors
We measured the fabric used in CORE SHIELD® innerwear (item no. 14-9964) in the two colors we sell: White and Black.
| Item | Wavelength range | White | Black |
|---|---|---|---|
| UV protection rate | 290–400nm | 97.1% | 98.7% |
| UPF | 290–400nm | 50+ | 50+ |
| Near-infrared protection rate | 780–2600nm | 88.6% | 87.6% |
For UV, black is slightly higher
For UV rays, Black was 1.6 points higher. Dark dyes absorb UV well, so with the same fabric, black lets less UV through. This is why so much UV-protective clothing is black.
Even so, White blocks 97.1%, and both colors are rated UPF 50+, the highest UPF category.
For near-infrared, there is almost no difference
For near-infrared rays, White was 88.6% and Black was 87.6%. The difference is 1.0 point, with White slightly higher.
Near-infrared rays are stopped not by color but by special ceramic microparticles derived from rare metals that are kneaded into the yarn. The near-infrared figure does not depend on making the color darker.
UV protection varies with color; near-infrared protection does not. That was the difference we found by measuring both colors.
So choose the color you like
White if you wear it under a white polo shirt, Black if you prefer a color that hides dirt. Whichever you choose, it still blocks 97%+ of UV and 87%+ of near-infrared rays.
For color transfer when wearing black innerwear under a white shirt, see “Can a black undershirt be worn under a white polo shirt?”, where we share the test results.
* UV values are test results from a third-party testing agency (KEKEN Test & Certification Center) under JIS L 1925; near-infrared values are averages over 780–2600nm measured by the material manufacturer. All values were measured on the fabric alone and do not indicate effects when worn.
* Research on the relationship between near-infrared rays and photoaging is still ongoing in dermatology. This product is clothing and does not prevent or improve age spots, wrinkles or sagging.
