When
            you balance the colours in a clip, you should always start with
            the darkest and lightest parts of the image. You may, for example,
            need to establish parameters for the black and white (luma) content
            to ensure that the intensity of the image is in accordance with
            established broadcast parameters. These parameters are known as black
               points and white points. You use the Black
            and White fields to establish black and white points.
         
         Black
               fieldModifies the luma in the image's shadows without
            affecting the chroma.
         
         White
               fieldModifies the luma in the image's highlights without
            affecting the chroma.
         
         To set black and white levels:
         
         
            - Sample the highlights in the image. To
               determine the white point, select a white that appears to be flat
               rather than reflective so that you obtain a more accurate reading.
               Do not use a highly reflective surface such as a window or metal
               surface as they are often too bright. Enable Plot and then sample
               the whites in the result clip.
               In the Basics menu, a
                  red plot line is displayed in the 2D luma histogram indicating the
                  luma value of the sampled whites in the result clip.
                
- While viewing the 2D luma histogram and
               the image, adjust the white level to modify the luma value and set
               the white point—drag left to darken the highlights and
               right to lighten them. The Plot sample is updated as you drag the
               field.
               TipYou can view both
                     the 2D luma histogram and 2D vectorscope to determine what adjustments
                     you need to make to the highlights. For example, if the white point
                     is set to an acceptable level in the 2D luma histogram but the sampled
                     chroma value shows an unwanted colour cast in the 2D vectorscope,
                     use the Highlights trackball to modify the chroma value in the highlights.
                     See  Removing Unwanted Colour.
                   
 
- Enable Plot and sample the shadows in
               the result clip to determine the black level. Sample the darkest
               part of the image to determine the black point.
               A red plot line is displayed
                  in the 2D luma histogram indicating the luma value of the sampled
                  blacks in the result clip.
                
- While viewing the 2D luma histogram and
               the image, adjust the black level to modify the luma value—drag
               left to darken the shadows and right to lighten them. The Plot sample
               is updated as you drag the field.
               TipOnce the black level
                     is set, you can use the Shadows trackball to adjust the chroma values
                     in the highlights while viewing the plot sample in the 2D vectorscope.
                     See  Removing Unwanted Colour.