The Adjustment Brush is perhaps the most powerful tool in Adobe Camera Raw. Use it to selectively alter areas of an image.
It behaves in much the same way as the Graduated Filter (note that the tonal settings for each are identical).
Except rather than plot a gradient, you paint a mask. Each mask is represented by a pin. These pins and their masks can be added to, altered, or deleted.
Adjustment Brush tips
- Check ‘New’ to start painting a fresh mask, ‘Add’ to continue painting a mask, and ‘Erase’ to remove parts of it.
- Hit Y to toggle the visibility of the currently selected mask overlay.
- Check Auto Mask for automated assistance when painting a mask. The tool will snap onto edges, lines and shapes.
- Use the number keys to quickly set a density for your brush: Hit 1 for 10%, 2 for 20% and so on.