Irradiance and dose: the specification that decides everything

Every LED mask product page leads with diode count and wavelength. Neither tells you how much light reaches your skin. The specification that does is irradiance, and almost nobody publishes it.

Dose in joules per square centimeter equals irradiance in milliwatts per square centimeter, multiplied by time in seconds, divided by 1,000.

So for the Omnilux Contour Face, which states roughly 30 mW/cm2: a ten-minute session (600 seconds) delivers about 18 J/cm2. That is a number. You can compare it to the doses used in published studies, you can argue about whether it is enough, and you can hold the manufacturer to it.

Now try the same calculation for the CurrentBody Series 2. It has 236 diodes and a ten-minute session. Irradiance: not published. Dose: incalculable. Not low, not high - unknowable, by anyone outside the company.

750 diodes sounds like six times 132. It is not six times the light, and it may not be more light at all.

• Nothing says each diode is equally powerful. A 750-diode array can be built from smaller, lower-output emitters. Count and total optical power are independent.
• Coverage area is fixed. A face is a face. More diodes over the same area means more, smaller sources - better uniformity, not necessarily more energy.
• Distance changes everything. Irradiance falls off rapidly with distance from the source. A rigid mask holding 648 diodes a centimeter off your cheekbone may deliver less there than a flexible mask with 132 touching the skin.
• Wavelength splitting dilutes it. 160 diodes across four channels is 40 per wavelength. 132 across two is 66.

Red light panel manufacturers publish irradiance routinely, usually with a distance table, because that is the number panel buyers compare on. Mask manufacturers collectively do not.

There is a charitable explanation and an uncharitable one. Charitably, a mask sits at skin contact so the distance question is simpler and the measurement is less standardized across the category. Uncharitably, a published number can be challenged and a diode count cannot. We cannot tell you which it is, and we note that one brand - Omnilux - manages to publish a figure anyway. Masks and panels compared.

A manufacturer's own irradiance number has not been independently verified. Measurement conditions, which wavelength it refers to, and the distance assumed can all vary. We label every such figure brand-stated for exactly this reason.

That is still not the same as publishing nothing. A number creates accountability: it can be measured, challenged and corrected. Silence cannot. We credit Omnilux for being checkable, not for having been checked.

1. Look for an irradiance figure first. If one exists, it is the most useful number on the page.
2. If there is none, stop treating diode count as a proxy. It is not one, and reading it as one is how people justify paying more for less.
3. Weight the shell material. With no irradiance published, contact distance is the one variable you can still reason about, and flexible beats rigid.
4. Use the clearance as the other filter. Which masks have records you can look up.
5. Ask the brand. If enough buyers ask for an irradiance figure, the category might start publishing one. That is not naive; it is how panel specs became standard.