Autodesk 62205-051408-9001 User Guide - Page 623

About Keying ❚❘❘ Hue A specific color from the color spectrum, disregarding its saturation or lightness. Saturation The purity of a given color. For example, the difference between a pastel and a pure color is defined by the amount of saturation. Chrominance Chrominance is defined by the hue and saturation of a pixel. Luminance Luminance is an image processing property that defines the brightness of a pixel. Expressed in percentages, 0% luminance is black and 100% luminance is white. Values between 0 and 100% define a range of grays. Colored pixels have a luminance value equivalent to the mean of their RGB values. Sharpness Sharpness can be defined as the visual sense of the abruptness of an edge. It highlights the detail in an image or image sequence. Softness Colors that fall within the softness range are partially transparent. These areas appear gray (a dark gray to light gray range) in the matte. For example, softness makes the transition between the foreground and background of a composition more convincing by softening what would otherwise look like an abrupt cut-out. Softness can also be used to retain transparent key-in materials or shadows that you want to appear in the result composition. Tolerance or Threshold The colors that fall within the tolerance or threshold range are transparent. These areas appear black in the matte. Computer Generated Imagery Images created or generated with a computer are referred to as Computer Generated (CG) images. About the Discreet Keyer The Discreet Keyer provides keying tools used to associate transparency values to a range of colors in the clip. You can use various color models, and adjust the ranges for each color channel individually. You can use the Discreet Keyer to work directly on the matte to fine-tune the key. You can shrink, erode, or blur the edge, or adjust the entire matte using gain, offset, and histogram controls. The Discreet Keyer includes color correction tools to remove color spill. For example, you can use color suppression to remove unwanted color, or use color shift to change the unwanted color to another color. To finesse the final result, you can adjust the blending of the front and background images using the Matte Curves, which are also an integral part of the Discreet Keyer. You can even use the Discreet Keyer to define a selection based on the matte created by keying an image. About the Diamond Keyer The Diamond Keyer gives you fine control over the most complex keying tasks. It depicts color distribution through all hues and across the luma range. Use the Diamond Keyer to extract a key based on luminance values or a color, and fine-tune the tolerance, softness, and sharpness of the key. 607