 ETTIH), which is in fact just a slight generalization of ETTR.With ETTR, exposure is maximized up to the constraint of preserving all highlights at the right edge of the histogram (a constraint implied by the hard saturation of the digital sensor).With ETTIH, exposure is maximized a bit further; the constraint is relaxed so that only the "highlights deemed important" are preserved before the right edge of the histogram, and the "highlights deemed unimportant" may fall into the saturation zone of the sensor.