Soft tissue illuminated by a headlight
Soft tissue (leg) contact-illuminated by an LED-panel headlight. The red hue results from lower tissue attenuation at that longer wavelength causing red light to re-emit. The yellow is due to stronger surface scattering and the greater spectral intensity of the LED in the yellow band. The staggered strips of red and yellow arise from the abnormality of the image stabilization of the iPhone 6S camera.
—Daqing (Daching) Piao, Oklahoma State University, Stillwater, OK, USA