Keying - Nuke 101: Professional Compositing and Visual Effects - page 312

Finally you need to adjust the Patch Black property until all your black patches
are filled.
12. Bring up the Patch Black property until all your black areas are filled with green.
The slider goes up to 5, but you need 10 to get the result you're after. To do this,
you can enter 10 in the field ( FIGURE 7.18 ).
Figure 7.18. A complete green image—the clean plate.
Now that you have a clean plate, you need to adjust the IBKGizmo settings to get
a nice-looking key. Let's move over to the IBKGizmo then.
13. Double-click IBKGizmoV3_1 to load its Properties panel into the Properties Bin.
14. View IBKGizmoV3_1 and its alpha channel in the Viewer.
Again, the first thing to take care of here is setting the screen color.
15. Change the Screen Type property to C-green.
You can already see that the alpha has some really good things happening in it.
First, the whole foreground (where the girl is) is indeed white. Also, all the fine
hair detail is preserved beautifully. There is just the noise in the black areas that
needs to be cleaned up.
The other properties ( FIGURE 7.19 ) worth mentioning include:
• Red Weight: This property changes the density of the generated matte by
adding or subtracting the red areas of the image.