v ref each curve reaches a plateau level when the exposure level reaches what is referred to here as a saturation exposure level for that detector ideally the three saturation exposure levels for the red green and blue detectors are approximately equal while the highlight detector saturation exposure level is significantly higher for example by a factor of two to ten the difference in saturation exposure levels is shown much higher here for emphasis it is by no means necessary to achieve the ideal to create an operative device depending on the circumstances there may be considerable variation in the approximately equal saturation exposure levels of the three color detectors each saturation exposure level will of course depend on the spectral sensitivities of the detectors and the color of the light being used for the measurement in the example given here the light has been taken to be any typical white illuminant returning to fig1 the significance of the difference in the saturation exposure levels will be described assume that the vertical color filter detector group 10 has been exposed to light of sufficient brightness to cause the red green and blue detector regions 14 16 and 18 to just reach but not exceed the threshold of their respective saturation exposure levels this is the level at which the three color detector regions have reached their maximum photocharge capacity or signal output level minimum voltage as the brightness increases beyond the threshold the three color detector regions become saturated and many of the excess electrons e or minority carriers generated in the vicinity of each of the respective saturated color detector regions are conducted away by an.