Clicking on the Saturation or Hue Wash displays in the Platinum Mega1 panel will bring these controls up on the Blue Display.
The main control is Hue wash. Turning this control anti-clockwise will gradually reduce the hue range in the picture. When turned to minimum, there will only be one hue or colour left.
The saturation values of the original picture will remain the same - only the hue will be affected. Now the master hue control will rotate all the hues around. There is a point where very convincing sepia-tone effects can be achieved.
Sometimes it is necessary to put a little colour into the white and black areas of the original picture - these will still be black and white from the hue wash as they have no hue to alter. To do this turn the Sat Wash control clockwise slightly. Now the master saturation control will alter the wash of colour in the whites and blacks.
Monitoring the picture with a vectorscope, when first experimenting with wash, will help understand the functions.
While Hue and Saturation wash affect the whole picture, it is still possible to use the six vector corrector underneath a washed picture. For example you could have a washed picture and still change the saturation of a green hedge thereby increasing the saturation in the sepia-tinted picture.