How to Fill with Color in GIMP

Filling an area with color is one of the most basic operations in GIMP, but there are multiple ways to do it depending on what you need. The Bucket Fill tool is the most common, but selection-based fills give more control. Here is when to use each.

Bucket Fill Tool

Press Shift+B to activate the Bucket Fill (or click the bucket icon in the toolbox). Then click on the area you want to fill.

The tool fills connected pixels that are similar in color to where you clicked. Key settings in Tool Options:

• Fill Type: Foreground color, Background color, or Pattern. Foreground color is most common.
• Threshold: How similar pixels need to be to get filled. Low threshold = only near-exact matches. High threshold = fills a wider range of colors.
• Sample Merged: When checked, the fill looks at all visible layers to determine edges, not just the active layer. Useful for filling on a separate layer while respecting content on other layers.
• Fill Whole Selection: If you have an active selection, fills the entire selection regardless of color - Ignores the threshold.

Fill a Selection

For precise color fills without the Bucket tool's color-matching logic:

1. Make any selection (rectangle, ellipse, lasso, etc.).
2. Go to Edit > Fill with Foreground Color, or press Shift+Backspace.
3. Or use Edit > Fill with Background Color for the background color.

This fills every pixel within the selection boundary with a flat solid color, regardless of what was there before. Deselect with Ctrl+Shift+A when done.

Fill an Entire Layer

To fill the whole layer with one color (useful for creating solid background layers):

1. Press Ctrl+A to select all.
2. Press Shift+Backspace to fill with the foreground color.
3. Press Ctrl+Shift+A to deselect.

Or even faster: with the Bucket Fill tool, hold Ctrl and click the canvas to fill the entire layer regardless of color matching (on some GIMP versions this behavior depends on whether "Fill whole selection" is checked).

Filling with a Gradient

The Blend tool (L) fills an area with a gradient between two or more colors.

1. Set your foreground and background colors to the gradient start and end colors.
2. Press L to activate the Blend tool.
3. In Tool Options, choose the gradient type (linear, radial, etc.) and shape.
4. Click and drag across the canvas to define the gradient direction.

In GIMP 2.10+, the gradient is interactive - you can drag the endpoints to adjust direction and length before committing by pressing Enter.

Filling with a Pattern

For tiled textures or repeating designs:

1. With the Bucket Fill tool active, change Fill Type in Tool Options to Pattern.
2. Click the pattern thumbnail in Tool Options to choose a pattern from the picker.
3. Click on the canvas (or use Edit > Fill with Pattern if you have a selection).

Patterns tile automatically to fill the area. GIMP includes several built-in patterns and you can import custom ones via Edit > Paste as > New Pattern.