How to Fix Perspective Distortion in GIMP

Photographing whiteboards, paper documents, or handwritten notes from an angle often results in skewed, unreadable images due to perspective distortion. This guide explains how to use GIMP's built-in Perspective Tool to flatten skewed photographs into straight, readable, rectangular documents, along with basic color adjustments to make your text pop against the background.

Step 1: Open the Image

  1. Launch GIMP.
  2. Go to File > Open and select the photograph of your whiteboard or document.

Step 2: Activate the Perspective Tool

  1. Select the Perspective Tool from the toolbox on the left, or press the keyboard shortcut Shift + P.
  2. Alternatively, navigate to the top menu and choose Tools > Transform Tools > Perspective.

Step 3: Align the Perspective Grid

  1. Click anywhere on your image to activate the perspective grid. You will see four corner handles appear along with a transform dialog box.
  2. In the Tool Options panel on the left, ensure the Direction is set to Normal (Forward).
  3. Click and drag each of the four corner points of the grid to match the four actual corners of the whiteboard or paper sheet in the photo.
  4. Once all four corners align with the edges of your subject, click the Transform button in the floating dialog box (or press Enter).

Step 4: Crop the Canvas

  1. Select the Crop Tool from the toolbox or press Shift + C.
  2. Drag a rectangle around the newly straightened whiteboard to remove any unwanted background elements (such as walls or desk space).
  3. Press Enter to apply the crop.

Step 5: Enhance Text Contrast and Readability

  1. Go to Colors > Desaturate > Desaturate to convert the image to grayscale if color is not required.
  2. Go to Colors > Levels.
  3. In the Levels window, drag the left black slider toward the center to make the handwriting darker, and drag the right white slider toward the center to make the whiteboard background bright and clean.
  4. Click OK once the text is crisp and legible.

Step 6: Export the Final File

  1. Go to File > Export As.
  2. Choose your preferred file format (such as PNG or JPEG), name your file, and click Export.