The intensity is not a linear function of the bit value, the intensity is more or less value^2.2, which does give ~1e6 to 1... See https://en.wikipedia.org/wik

The intensity is not a linear function of the bit value, the intensity is more or less value^2.2, which does give ~1e6 to 1... See https://en.wikipedia.org/wiki/Gamma_correction https://en.wikipedia.org/wiki/Gamma_correction for the gory details.