Paint with Velocity Gradient Dynamics in GIMP

GIMP allows you to dynamically cycle through a gradient based on the speed of your cursor or stylus. By linking brush velocity to the color output in GIMP’s Paint Dynamics system, moving your brush slowly applies colors from one end of a gradient, while rapid strokes transition toward the opposite end. This guide provides a straightforward method to configure, map, and paint with velocity-based gradient dynamics in GIMP.

Step 1: Select Your Paint Tool and Gradient

  1. Select the Paintbrush tool from the Toolbox or press P.
  2. Open the Gradients dockable dialog (Windows > Dockable Dialogs > Gradients).
  3. Click on the gradient you want to use for your brush strokes.

Step 2: Create a Custom Paint Dynamic

Default dynamics in GIMP are locked from editing, so you must create a new dynamic preset:

  1. Open the Paint Dynamics dialog by navigating to Windows > Dockable Dialogs > Paint Dynamics.
  2. Click the Create a new dynamics button (the paper icon at the bottom of the dialog).
  3. The Paint Dynamics Editor will open automatically. Name your preset (e.g., "Velocity Gradient").

Step 3: Map Velocity to Color

In the Paint Dynamics Editor, you will see a matrix of inputs (such as Pressure, Velocity, and Direction) against outputs (such as Size, Hardness, and Color):

  1. Locate the Color row in the matrix.
  2. Check the box at the intersection of the Velocity column and the Color row.
  3. (Optional) Click the arrow next to the matrix to open the dynamic curve editor if you want to fine-tune how quickly the gradient changes relative to your stroke speed.

Step 4: Configure Tool Options

  1. Return to the Tool Options panel for the Paintbrush.
  2. In the Dynamics dropdown, select your newly created "Velocity Gradient" preset.
  3. Scroll down and expand the Color Options section in Tool Options.
  4. Ensure the gradient preview displays your desired color scheme.
  5. Set the Repeat mode according to your preference:
    • None: Velocity scales smoothly from start to end.
    • Sawtooth wave: Cycles through the gradient repeatedly as speed increases.
    • Triangular wave: Alternates back and forth through the gradient.

Step 5: Test and Calibrate

Draw strokes on your canvas with varying speeds:

  • Make a slow, deliberate stroke to paint with the beginning colors of the gradient.
  • Quickly flick or swipe your brush across the canvas to watch the colors shift to the end of the gradient.
  • Adjust brush size and spacing in the Tool Options to make the color transitions smoother or sharper based on your project requirements.