Substituting the Draper point into this equation produces a frequency of 83 terahertz, or a wavelength of 3.6 µm—which is well into the infrared, and completely invisible to the human eye. However, the leading edge of the blackbody radiation curve extends, at a small fraction of peak intensity, to the near-infrared and far-red (approximately the range 0.7-1 µm) which are weakly visible as a dull red.[5]