What is keying in Nuke?

What is keying in Nuke?

Nuke’s image-based keyer (IBK) uses the pixel values of the compositing images, instead of a color-pick, to generate the best matte for the image you want to extract.

How do you use chroma key in Nuke?

Quick Key

1. Start Nuke and read in the foreground and background images.
2. In the ChromaKeyer Properties panel, click the color swatch next to screen color to activate the eye dropper.
3. Ctrl/Cmd+Shift+click and drag a rectangular area over the green pixels in the Viewer.

How do I use Nuke keyer node?

Select which keying tool you want to use for keying your sequence:

1. red keyer – use the red channel to pull the key.
2. green keyer – use the green channel to pull the key.
3. blue keyer – use the blue channel to pull the key.
4. redscreen – subtract the red channel from other channels.

What is keying in compositing?

– Keying is a special compositing effect that happens when we take a part of a video and make it transparent. We can choose this part of the video based on color, luminance or even a mask. When we choose the part of the video to be made transparent, based on color this is known as Chroma Keying.

How do you set a nuke key?

Nuke switches to autokey mode: when you change the parameters value at another frame, it automatically inserts another keyframe for you. You can also set a key for all the controls in a node. To do so, right-click on a node’s properties panel and select Set key on all knobs.

How do you use the Cryptomatte Nuke?

Nuke Usage

1. Load a Cryptomatte exr file, such as the sample images, using a Read node.
2. Select it, and tab create a Cryptomatte gizmo.
3. View the output of the gizmo. You should see a preview image (pictured).
4. Use the eyedropper with the ‘Picker Add’ knob to select objects.

How do I remove a green screen Nuke?

ChromaKeyer is a green and bluescreen keyer that can take advantage of the local GPU. Use the screen color selector to choose a color from the Source input to use as the blue/green screen color. To remove blue/green spill from the foreground object, use the despill bias control to pick skin tones from the source.

What is Despill bias?

The despill bias allows you to specify a color from the image, separate from the alpha bias, to improve the overall despill for the matte. Typically, you should pick skin tones or hair colors for the despill bias.

What is IBK color in nuke?

It is set to blue by default, but you can change it to green. Now the aggressiveness of the removal is controlled by the size slider.

What is IBK gizmo?

The IBK keyer consists of two nodes: IBKColor and IBKGizmo. IBKColor creates the clean plate from the blue- or greenscreen image, and IBKGizmo pulls the key. Note: The output from IBKGizmo is a premultiplied image with an alpha channel – it does not composite the foreground over the background.