Clip Control works by calculating the factor against the raw white level, so that no corrected pixel will exceed the value of the white level.

The η characteristic value, white level value, contrast value and black level value are input for adjusting the luminance characteristics of input video signals.

This factor would then be used in the final calculation to prevent any pixel's value from exceeding the white level.

There is also a level beyond which the photosite will not register a change in light intensity even if the light does keep getting brighter - this is the white level.