HowLightsmartworks

Every figure on this page is a physical measurement, not a model.

Thermal

ThermaData WiFi data logger with a K-type thermocouple positioned beneath the fabric on a black absorptive panel. Solar irradiance at the panel was read as 1,117.7 W/m².

A short-pass filter transmits wavelengths shorter than its cut-off and blocks longer ones. Placed between the LED source and the fabric, a 650 nm short-pass filter lets the UV, violet, blue and green light through and removes the red and near-infrared. The detector is then read only in the 650–950 nm window.

• If the fabric merely transmits or reflects light, the 650–950 nm reading stays near zero — there is nothing in that band to transmit. That is the control result: 0.01 mW/cm².
• If the fabric absorbs shorter-wavelength light and re-emits at longer wavelengths, the detector sees it. That is the UV2RED result: 1.87 mW/cm², peaking at 776 nm.
• The test is designed to answer one question — is the fabric generating red/NIR? — under a laboratory source. It does not replicate outdoor irradiance, angle or distance.

Three woven constructions under sunlight

Same yarn platform, three colours, three emission profiles. Measured under real sunlight with the HPCS330Pro; no filter. Ee is irradiance in mW/cm²; FWHM is the width of the emission band at half its peak.

Curves are generated from the measured peak and FWHM (as in the source record). Heights are scaled so each curve's area is proportional to its measured Ee. Colour changes both how much is emitted and where the band sits.

Woven fabric versus a standard hat

A separate comparison recorded Midnight Sun woven fabric at 1.87 mW/cm² of red/NIR against 0.27 mW/cm² for a standard hat over 650–900 nm — about seven times more. The record does not state the date, filter or lighting conditions for that comparison, so we list it here rather than in the main text. It says nothing about the direction the light travels.

Where a field is blank, the source record does not contain it. We have not filled gaps.

Accredited third-party laboratories, AATCC TM 183 (erythemally weighted UV transmittance). All 13 rated UPF 50+.

UPF is an uncapped ratio; values well above 50 indicate essentially complete blocking and should be read as "≥50+".

Lumia Blue 4% (C4L3, 100% polyester, 140 g/m²) versus a blue control dyed to match (126 g/m²). The UV2RED sample is the heavier of the two. The source record attributes the difference to conversion; weave, dye chemistry and air gap were not separately controlled, so treat the mechanism as indicated, not established.

Test 2 · dark UV2RED versus light control

Photo documentation

Irradiance accumulates over time. The conversion is simple: mW/cm² × 3.6 = J/cm² per hour. Photobiomodulation studies commonly discuss doses in the single-digit J/cm² range; a figure of 4–10 J/cm² is often referenced. Using the woven readings above:

Caveats. These are irradiance values measured at the fabric under the recorded sunlight, not dose delivered to tissue. The reference range comes from device studies with fixed wavelengths, distances and durations; it is not a Lightsmart dosing claim. Skin, garment fit, angle and cloud all change what actually arrives. We include the arithmetic because people ask for it, not as a target.

Photobiomodulation — mechanisms and reviews

1. de Freitas LF, Hamblin MR. Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE J Sel Top Quantum Electron. 2016;22(3):7000417. PMC5215870
2. Hamblin MR. Mechanisms and mitochondrial redox signaling in photobiomodulation. Photochem Photobiol. 2018;94(2):199–212. PMC5844808
3. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337–361. doi:10.3934/biophy.2017.3.337
4. Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016;9(11-12):1273–1299. PMC5167494
5. Huang YY, Chen AC, Carroll JD, Hamblin MR. Biphasic dose response in low level light therapy. Dose Response. 2009;7(4):358–383. doi:10.2203/dose-response.09-027.Hamblin
6. Dompe C, et al. Photobiomodulation — underlying mechanism and clinical applications. J Clin Med. 2020;9(6):1724. doi:10.3390/jcm9061724
7. Lohr NL, et al. Enhancement of nitric oxide release from nitrosyl hemoglobin and nitrosyl myoglobin by red/near infrared radiation. J Mol Cell Cardiol. 2009;47(2):256–263. doi:10.1016/j.yjmcc.2009.03.015

UV protection and sunlight

8. AATCC TM183 — Transmittance or Blocking of Erythemally Weighted Ultraviolet Radiation through Fabrics. aatcc.org
9. Skin Cancer Foundation — Sun-protective clothing and UPF. skincancer.org
10. NREL — Reference solar spectral irradiance, ASTM G-173. nrel.gov

Lightsmart test records

Filter bench test (Charlotte, NC, Jan 27, 2026); outdoor red/NIR uplift test (Charlotte, NC); woven emission profiles; thermal comparisons; 13 UPF laboratory reports (Intertek Taiwan TWNT02198274, TWNT02198282, TWNT02199359, TWNT02199362; Precision Testing Labs 38684–38687, 41575, 41576, 49305, 49306). Copies of laboratory reports are available on request via lightsmart.tech.

• Small samples. Most results are single fabrics measured in single sessions. They demonstrate the effect; they are not population statistics.
• Bench versus body. The filter test and thermal tests were run on swatches over instruments or panels, not on people wearing garments.
• Directionality was not measured. We do not know what share of generated light leaves toward the skin versus away from it.
• Optical, not biological. The measurements show the fabric emits red/NIR. They do not measure any effect on the wearer.
• Confounds in thermal tests. Paired fabrics differ in weight and construction, not only UV2RED content.
• Curve shapes. Spectral curves on this page are generated from measured peak and width values, as in the source record, not traced from raw spectrometer exports.
• Product transfer. Results from one construction or colour (knit, woven, mesh) do not transfer to another. Colour-specific data for the garments shown is not on this page.
• Missing fields. Some tests lack a recorded date or location. Where that is so, the field is omitted, not estimated.

Is UV2RED a coating or a treatment?

No. It is a photonic material incorporated into the polyester fiber itself when the yarn is made. There is no coating or finish to wear off.

Does it need charging, a battery or an app?

No. It needs light. There is nothing to charge and nothing to do.

Is "187×" how much more red light I get?

No. It is the ratio of two readings in a filtered bench test where the control reads essentially zero. It proves the fabric generates red/NIR; it does not describe your exposure in sunlight. The outdoor figure is +32%.

Is UPF the same thing as conversion?

No. UPF measures how much UV does not pass through. Conversion measures how much red/NIR the fabric generates. The fabric is rated UPF 50+ and, separately, measured to generate red/NIR.

Does all the blocked UV become red light?

No. Some is reflected or scattered; some absorbed energy becomes heat; a portion is re-emitted as red/NIR.

Does it work through dark colours?

The three woven colours measured all emitted red/NIR, with different peaks and intensities. Colour changes the result; it does not switch it off.

Does it work indoors?

The bench test used a laboratory UV/short-wave source, so the mechanism does not require the sun. Output under ordinary indoor lighting has not been measured on this page.

Is this the same as a red-light panel?

No. Panels deliver a fixed wavelength at a controlled distance and dose. Fabric output is driven by sunlight and varies with it. The research base cited above is from devices.

Is UPF 50+ a substitute for sunscreen?

UPF applies to the skin the fabric covers. Exposed skin still needs protection.