Using the Split Viewer Node in Blender Compositor

This article explains how to use the Split Viewer node in Blender's Compositor to perform real-time before-and-after comparisons of your color grades and compositing setups. You will learn what the node does, how to set it up step-by-step, and how to adjust its parameters to effectively evaluate adjustments between original and processed renders.

What is the Split Viewer Node?

The Split Viewer node is an output-utility node in Blender’s Compositor designed specifically for visual comparison. It takes two distinct image inputs—such as an ungraded base render and a color-graded result—and displays them divided across a single frame in the Backdrop or the Image Editor's Viewer node output. This allows you to inspect changes without needing to toggle node mutes on and off.

Step-by-Step: Comparing Before-and-After Grades

Follow these steps to set up a side-by-side comparison in the Blender Compositor:

  1. Open the Compositing Workspace: Navigate to the Compositing tab at the top of Blender and ensure the Use Nodes checkbox is enabled in the header.
  2. Add the Split Viewer Node: Press Shift + A, navigate to Output, and select Split Viewer. Place the node near the end of your compositing chain.
  3. Connect the "Before" (Original) Image: Connect the socket of your raw source (such as the Image output from your Render Layers or Image input node) into the Image 1 input socket of the Split Viewer node.
  4. Connect the "After" (Graded) Image: Connect the final output of your color grading nodes (such as Color Balance, RGB Curves, or Color Correction nodes) into the Image 2 input socket of the Split Viewer node.
  5. Enable Backdrop View: Ensure Backdrop is checked in the Compositor header to see the split view directly behind your node tree, or open an Image Editor panel and set the source to Viewer Node.

Adjusting Split Settings

The Split Viewer node provides simple controls to customize how the split is displayed:

  • Type (X / Y): Choose between an X (vertical dividing line, comparing left and right) or Y (horizontal dividing line, comparing top and bottom) orientation.
  • Factor: Adjust the slider to reposition the split line across the frame. A factor of 50% divides the screen evenly in half, while lowering or raising the value reveals more of Image 1 or Image 2 respectively.