 On the angle-of-incidence scale (horizontal axis), Brewster's angle is where (red) falls from 180° to 0°, and the critical angle is where both and (red and blue) start to rise again.To the left of the critical angle is the region of "partial" reflection; here both reflection coefficients are real (phase 0° or 180°) with magnitudes less than 1.To the right of the critical angle is the region of "total" reflection; there both reflection coefficients are complex with magnitudes equal to 1.