When you create a matte for the front clip, the Keyer automatically creates a matte for the back clip to specify which part of the back clip is used for the composite. By default, the back matte is the inverse of the front matte.
You can adjust the luminance of the front matte and back matte separately in the Blending menu in the Result node in the schematic. For example, increase the luminance of the back matte so that more of the back clip shows through at the edges of the key. This creates a better blend at the edges of the key.
To adjust the luminance curve:
- Double-click the Result node in the schematic.
The Luminance curve appears.
(a) Front matte curve (b) Back matte curve (c) Front/Back box
- Use the Viewing box to select the image you want to view as you adjust the curves.
Select: To view: Result The composite clip. Matte The front matte. You cannot see changes made to the back matte when this view is selected. Bmatte The back matte. You cannot see changes made to the front matte when this view is selected. Comp The composite with a coloured background. The default colour is black. To select a different colour, click the colour pot to the right of the Comp button. The colour picker appears. Key In The image that was used to pull the key. Back The background image that is revealed when the front is keyed. Front The image to which you applied the key. - To adjust the luminance curve for the front matte, select Front from the Front/Back box. To adjust the back matte curve, select Back. Alternatively, click a curve to select it.
The selected curve changes to white.
(a) 255 (White) (b) Output (remapping of luminance values) (c) 0 (Black) (d) 0 (Black) (e) Input (current luminance values) (f) 255 (White)
- Click a point to display its tangent handle and drag the handle to adjust the curve. Use other modes in the Tools box to further adjust the curve, adding or deleting points or breaking tangent handles, as needed.