When it comes to light therapy for acne and other conditions, some websites throw around very scientific sounding terms that can be intimidating to normal people. A couple of these are 415nm and 660nm. Those terms simply define the color of the light as follows:

A little more explanation:

The sun emits an unthinkable amount of energy, generally called electromagnetic radiation or the electromagnetic spectrum. This energy travels to earth in waves, and the wavelengths are measured in meters.

Most of the sun’s energy (radiation) is harmful to us (gamma rays, x rays, most of the UV rays), and so is blocked by our atmosphere. But some of this tremendous energy reaches earth, and we call the visible portion of this energy “light.”

The wavelengths of visible light are tiny, ranging from 400 to 700 billionths of a meter. A billionth of a meter is called a nanometer, or nm.

White light, as you likely know, contains all the colors of the rainbow. And so a color can be defined by a range of tiny wavelengths, in nanometers, or nm, like this:

So “415nm irradiation” is very simply violet light, and that’s really all there is to it. Calling it “radiation” makes it sound potentially dangerous and expensive, but “radiation” is just energy, in this case light energy, and it’s not dangerous or expensive, in fact, it’s life sustaining and it’s free. If you step outside into the sunlight (always avoid sunburn), you will be bathed in 415nm and 660nm light. That may be one reason your acne improves in the spring and summer months. Another reason may be the Vitamin D produced when the sun bathes your skin.

Does this mean that any light that shines blue or violet contains 415nm light, and any light that shines red contains 660nm light? That will be a topic of another post.

Photos courtesy of Sci-ART-Global.com – Understanding Color Therapy