What is the primary use of the Healing Brush tool?

The Healing Brush tool is primarily designed to correct imperfections in photographs by blending them seamlessly with surrounding areas. When using this tool, the user can paint over blemishes, scratches, or other unwanted elements in an image. The Healing Brush samples the nearby pixels, taking into account the texture, lighting, and shading to create a patch that matches the original context of the image. This blending effect allows for a more natural and cohesive result, making it especially useful for retouching portraits or restoring old photographs.

The other options address various functions in Photoshop but do not align with the Healing Brush tool's capabilities. For instance, filling a selection with color relates to the Paint Bucket tool, creating gradients refers to the Gradient tool, and painting over unwanted areas aligns more closely with the Clone Stamp tool, which replicates pixels rather than blending them. The unique feature of the Healing Brush tool is its ability to blend imperfections in a way that looks organic and unobtrusive, making it an essential tool for photo correction tasks.