2017

Extracting a Custom Colour
Use the Custom colour channel option in the Channel Keyer to select the colour to be extracted from the
key-in clip. This option can give good results when keying transparencies, particularly by experimenting
with the Softness and Colour Spread values.
To create a key by extracting a custom colour:
1 From the Start Mode dropdown list, select Reset to Channel and click Confirm.
The Channel keyer processing pipeline is displayed in the schematic view.
2 Double-click the Channel Keyer node.
The Channel controls appear.
(a) Channel Mode box (b) Average Colour pot (c) Softness field (d) Colour Spread field
3 Select Custom from the Channel Mode box.
4 Click the Average Colour pot.
The cursor changes to a colour picker.
5 Click the image to select a single colour, or drag the colour picker across a region to obtain the average
of the colours encountered by the colour picker. Try selecting different colours in the background area
to get the best result.
TIP To keep shadows, click just outside them. To remove shadows, click inside them.
6 Adjust the softness for the key using the Softness field.
Increasing softness raises the level of grey in the matte. Lowering it makes the matte sharper.
7 Adjust the colour spread for the key using the Spread field.
Increasing the colour spread value extends the range of colours extracted from the key-in clip.
8 Click the Result node so that you can see the changes in the right side viewer. If you do not see the
result, see
Setting Up Viewports for Keying (page 679).
NOTE To improve the key at this point, try adjusting it with the histogram in the 2D Histogram node. See
Adjusting the Luminance of the Key (page 701).
Creating a Key by Extracting a Range of Colours with the HLS,
YUV, RGB and RGBCMYL Keyers
Another technique for creating a key is to extract a range of colours from the key-in clip. Use this technique
for clips where the colour you are extracting contains impurities.
When you build a key by defining a colour range, you can use one of four colour models: RGB, YUV, HLS,
or RGBCMYL. Each model interprets the key-in clip differently and gives a slightly different result.
After you choose a colour model, you set a range of colours to become partially transparent in the key-in
clip to soften the transition between the front and back clips. This is called the softness range. All pixels in
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