Saturday, March 5, 2016

Beauty is Only Skin Deep: The Science of Lighting Faces

The images below are the same face. True or False?

Answer: FALSE.

Same person, but four different faces. Strange but true.

In this blog post I will explain why. I'll also cover why messing with color balance in Photoshop doesn't fix problems like red blotches on faces.

These photos were taken with light of increasing red content. The first is 8600K (blue sky). The second image is 6000K (diffuse sunlight). Third pic is 3800K (bright white fluorescent), and lastly 2600K (incandescent).

The first image is essentially a picture of the top surface layer of my skin. Each successive picture captures a deeper slice. The last image includes some of the subsurface features, which is why it is so red. It is actually showing the blood vessels beneath the skin. Note that each image was white balanced to styrofoam (perfect white), so the colors are nearly equivalent. If you tried to change the color balance to get rid of the redness in my face in the last image, you would royally mess up all the rest of the colors, including the blues and whites of the eyes. In redder light, my face actually gets redder because you can see all the way through to the blood vessels, making places with lots of shallow blood vessels (like my nose, cheeks and chin) stand out.

Most of us think that if we just play with the color balance we can take a red-faced image and make it look like the smooth skin of the sunlight pictures. But it just doesn't work. They are different faces! (I mean different layers of the face.)

Beauty is only skin deep. 


Spectrum IPL Image
Diagram showing the penetration length of different colors into the skin increasing for longer wavelengths.

Weird translucent cave fish
In fact, if you could take a picture of yourself with a near infrared camera you could see right into your skull! We would all look like translucent aliens or the weird see-through fish that live in caves.

White (actually translucent) skin shows whatever is underneath, whether blue veins or red blood vessels or the smoothing subcutaneous fat layer that hides those things in women and makes them look more beautiful to the eye, even in warm lighting. But for most folks without perfect skin, the color temperature of the lighting can really make a difference. However, the darker your skin pigment, the less difference the color of the light makes because light of all colors is being absorbed by melanin in the basal layer. So skin pigment is one of nature's secret ways of creating beautiful skin.

Some babies have very little skin pigmentation. Traditional wisdom says "babies look best in natural light." What they mean to say is, "If you shine red light on the little alien you can see right through it." Ok, maybe not that. But the truth is, unless you find blood vessel distributions fascinatingly beautiful, use high color temperature (cool) lighting, like diffuse sunlight, a xenon flash, and "daylight" LEDs or fluorescents.

Otherwise you might get pics like this.
Why is his face so red? ...Maybe he just farted and he's embarrassed.

Conclusion: Got see-thru skin? Avoid incandescent lighting.

Unless you are a girl with perfect skin.

Below is a picture of Nicole, age 11. Even in 2600K lighting her skin looks flawless, because it pretty much is. The fun of using the 2600K lighting is that her strawberry blond hair looks even more red. But that look in the eyes...hmm. She's up to something.
Mischievous girl age 11, 2600K lighting


To convince yourself that I'm not lying, go get an RGB color changing LED light bulb. Take a black and white photo of your fair-skinned model with the blue light on. Then do the same for the red light. Make sure you are shooting with the aperture wide open and maximum resolution. Compare the images at high resolution and you will see that the red image has a different kind of structure to the face. Red light really gets under the skin.


  1. This is really interesting! I never understood the "why" before and you explained it very clearly!

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