Sharpness

Sharpening helps a photo that's a little soft — from a slightly missed autofocus, a touch of camera shake, or simply the natural softening that happens when an image is resized or compressed — look noticeably more defined, without needing any editing software. It works by exaggerating the contrast right at the edges in an image (a technique called unsharp masking): where a dark area meets a light one, sharpening pushes the dark side slightly darker and the light side slightly lighter right along that boundary, which the eye reads as added crispness even though no new detail was actually created.

That's also its fundamental limit, and worth being upfront about: sharpening can make a slightly soft photo look crisper, but it cannot bring back detail that was never captured in the first place — a badly out-of-focus or heavily motion-blurred photo will not become sharp, it'll just become a more obviously blurry photo with harsher edges. Unlike the other adjustments on Forge, this one isn't a built-in browser filter; it's a real 3×3 convolution computed pixel-by-pixel across the image, blended in gently at low slider values so it stays subtle rather than introducing harsh halos around every edge. The slider runs from 0 (no change) to 10 (aggressive), and because it's genuine pixel math rather than a GPU-accelerated filter, very large photos are automatically scaled down slightly on load to keep it responsive as you drag.

All of this runs in your browser — nothing is uploaded. For sharpening alongside brightness, contrast, saturation, or hue adjustments, see the combined Image Adjustor.