How to Pin Sample Points in GIMP

GIMP allows you to place up to four persistent inspection points on an image to monitor precise color values in real time as you edit. This guide explains how to open the Sample Points dialog, place inspection points directly from the rulers onto your canvas, interpret the live color readouts, and manage or remove points when your task is complete.

1. Open the Sample Points Dialog

To view the data from your inspection points, you must first display the Sample Points dialog:

  • Navigate to the top menu and select Windows > Dockable Dialogs > Sample Points.
  • The panel will open, displaying slots for up to four sample points, which will remain empty until points are placed on the canvas.

2. Place Sample Points on the Canvas

Ensure that image rulers are visible (View > Show Rulers or Ctrl + Shift + R / Cmd + Shift + R).

  • Hold down the Ctrl key (or Cmd on macOS).
  • Click inside either the horizontal or vertical ruler and drag the cursor onto the canvas.
  • As you drag, crosshairs with a small coordinate display will appear. Release the mouse button over the exact pixel you want to inspect.
  • A numbered crosshair (1 to 4) will remain pinned to the canvas at that location.
  • Repeat this process to add up to four independent sample points. If you attempt to drag a fifth point, GIMP will not allow it until an existing point is deleted.

3. Read and Adjust Color Information

Once placed, each point's data appears in the Sample Points dockable dialog:

  • Color Models: Click the dropdown menu next to each sample point row in the dialog to toggle between color spaces, such as Pixel, RGB (0–255), RGB (percent), HSV, and CMYK.
  • Sample Average: By default, GIMP samples a single pixel (1x1). To smooth out noise or texture, switch to the Color Picker tool, check Sample average in the Tool Options dock, and adjust the radius to make the inspection points calculate the average color of a larger area.

4. Move or Delete Sample Points

  • To Move: Hold Ctrl (or Cmd), hover over an existing crosshair until the move indicator appears, then click and drag the point to a new location.
  • To Delete: Hold Ctrl (or Cmd), click the sample point crosshair, and drag it entirely off the canvas back into the ruler area before releasing the mouse button.