Nodes Combine/Separate

Tous ces nodes font essentiellement la même chose :

  • Separate : divise l’image en ses composantes de canal de couleur.
  • Combine : Re/combiner une image à partir de ses composantes de canal de couleur.

These nodes can be used to manipulate each color channel independently. Each type is differentiated in the applied color space.

In compositing and texture context each node supports the Alpha channel. In the texture context only RGB color space is available. In the shading context of the Blender internal adds HSV and the Cycles shading context offers an additional pair of nodes to combine/separate a vector (XYZ).

The Combine nodes could also be used to input single color values. For RGBA and HSVA color spaces it is recommended to use the Node RGB. Some common operation could easier be executed with the Nodes Color.

Nodes Separate/Combine RGBA

../../../../../_images/compositing_types_converter_combine-separate_combine-rgba-node.png

Node ombine RGBA

../../../../../_images/compositing_types_converter_combine-separate_separate-rgba-node.png

NOde Separate RGBA

Input/Output

Image
Entrée / Sortie image standard.
  • R (Red)
  • G (Green)
  • B (Blue)
  • A (Alpha)

Propriétés

Ce node n’a pas de propriétés.

Exemples

../../../../../_images/compositing_types_converter_combine-separate_example-combine-rgba.png

An example of blurring the alpha channel.

In this first example, we take the Alpha channel and blur it, and then combine it back with the colors. When placed in a scene, the edges of it will blend in, instead of having a hard edge. This is almost like anti-aliasing but in a three-dimensional sense. Use this node setup, when adding CG elements to live action to remove any hard edges. Animating this effect on a broader scale will make the object appear to « phase » in and out, as an « out-of-phase » time-traveling sync effect.

Nodes Separate/Combine HSVA

../../../../../_images/compositing_types_converter_combine-separate_combine-hsva-node.png

Node Combine HSVA.

../../../../../_images/compositing_types_converter_combine-separate_separate-hsva-node.png

Node Separate HSVA.

Input/Output

Image
Entrée / Sortie image standard.
  • H (Hue)
  • S (Saturation)
  • V (Value)
  • A (Alpha)

Propriétés

Ce node n’a pas de propriétés.

Nodes Separate/Combine YUVA

../../../../../_images/compositing_types_converter_combine-separate_combine-yuva-node.png

Node Combine YUVA.

../../../../../_images/compositing_types_converter_combine-separate_separate-yuva-node.png

Node Separate YUVA.

Input/Output

Image
Entrée / Sortie image standard.
  • Y (Luminance)
  • U (U chrominance)
  • V (V chrominance)
  • A (Alpha)

Propriétés

Ce node n’a pas de propriétés.

Nodes Separate/Combine YCbCrA

../../../../../_images/compositing_types_converter_combine-separate_combine-ycbcra-node.png

Node Combine YCbCrA.

../../../../../_images/compositing_types_converter_combine-separate_separate-ycbcra-node.png

Node Separate YCbCrA.

Input/Output

Image
Entrée / Sortie image standard.
  • Y (Luminance)
  • Cb (Chrominance Blue)
  • Cr (Chrominance Red)
  • A (Alpha)

Propriétés

Mode
ITU 601, ITU 709, Jpeg

Exemples

../../../../../_images/compositing_types_converter_math_multiply.png

An example of the scaling the Luminance channel.

This example has a Math (Multiply) node increasing the luminance channel (Y) of the image to make it brighter.

Astuce

If running these channels through a Color Ramp node to adjust value, use the Cardinal scale for accurate representation. Using the Exponential scale on the luminance channel gives a high-contrast effect.