White desaturation is available on the third control on the right of the panel. Black desaturation is available on the fourth control on the right of the panel. Black and White slope are also available.
We all know the problem of having parts of the picture, especially the lowlights, having a colour cast. This can be time-consuming to correct using primary lift without messing up the mid-tones. The Desat(urate) controls on Mega 1 are a set of tools to help to correct this situation. As you turn the Desat Black control clockwise, the colour will be taken out of the lowlights of the picture. The further you turn the control, the further up the luminance scale this desaturation goes. Naturally, this is not a hard on/off effect - the desaturation ÒrampsÓ into effect. You can see what is happening by looking at a greyscale ramp with a large colour cast to it. As you turn the Desat Black knob you will see how the desat attacks the colour cast. You also have control of the ÒrateÓ of this attack. The control called ÒSlopeÓ in the Mega 1 panel in Platinum will allow you to change the attack from a hard on/off effect to a very gradual desaturation as the brightness decreases. Desat White works in the same was except it comes in from the top of the luminance range (White) and works down the brightness scale. These controls have enough range to take the whole picture to monochrome