Sharpness

Sharpness describes how abruptly brightness or color transitions occur at edges within an image. Higher edge contrast produces a "sharp" appearance with clearly defined details, while gradual transitions create a "soft" or blurry look. Lens optical quality, focus accuracy, camera shake, and post-processing all influence the final sharpness of an image.

• Unsharp Mask (USM): Subtracts a blurred copy from the original to isolate edge information, then adds that edge data back with adjustable Amount, Radius, and Threshold parameters controlling the effect's intensity and scope
• High-pass filter method: Extracts only high-frequency components (edges) and blends them back using Overlay or Soft Light modes. This approach enables non-destructive sharpening through layer compositing in tools like Photoshop
• Over-sharpening artifacts: Excessive sharpening produces visible halos (bright outlines along edges) and amplifies noise, creating an unnatural appearance. Appropriate strength varies by output medium, such as web, print, and screen

One approach to RAW processing applies sharpening in stages: capture sharpening (compensating for the anti-aliasing filter), creative sharpening (emphasizing specific details), and output sharpening (optimized for the final delivery medium).