Photo Sharpener and Enhancer

Sharpen a photo without making it look fake

Every photo taken on a phone is softened twice: once by the lens and the sensor, and again by the compression the camera applies when it saves a JPEG. The result is a picture that looks acceptable on a small screen but slightly mushy when printed or viewed at full size. Sharpening fixes that by increasing the contrast along edges, which the eye reads as extra detail. Done gently it makes a portrait look crisp and a document look readable. Done too strongly it produces bright halos around dark objects and a crunchy, sandpaper texture on skin. This tool exposes the amount and the radius separately so you can find the point where the picture looks better and stop there.

How unsharp masking works

The technique is called an unsharp mask, a name that comes from the darkroom process of subtracting a blurred copy of an image from the original. The tool makes a blurred copy of your photo using a box blur, subtracts it from the original to find the edges, and then adds those edges back with a strength you control. The radius slider sets how wide the blurred copy is, which controls whether the effect targets fine texture such as hair and fabric or broader edges such as the outline of a face. A radius of one pixel is best for recovering detail in a photo that is already sharp but slightly soft. A radius of three or four is better for a scanned document or a photo that has been resized down, because the edges are wider.

Fix brightness, contrast and colour first

Sharpening amplifies whatever is already there, including noise and dull colour, so the order matters. Use the noise reduction slider first if the photo was taken in low light, because sharpening a grainy photo makes the grain look like confetti. Then adjust brightness and contrast: a photo that is slightly under-exposed often looks sharper simply because the mid-tones have more separation. Saturation and warmth come last. The warmth slider shifts the red and blue channels in opposite directions, which is useful for photos taken indoors under yellow bulbs or outdoors under heavy shade.

The presets, and when to use each

Gentle applies a small amount of sharpening with a one pixel radius and no colour change; it is the safe default for portraits and everyday photos. Crisp raises the amount and adds a little contrast, which suits product photos and screenshots of text. Strong pushes both sharpening and contrast further and is intended for documents and scanned pages where legibility matters more than natural skin tones. Document mode combines a higher radius with a contrast boost and a slight desaturation, which removes the yellow cast that phone photos of paper usually have and makes black text stand out. Original resets everything to zero so you can compare.

What sharpening cannot do

If a photo is blurred by motion, by being out of focus, or by being enlarged from a tiny thumbnail, sharpening will add edge contrast but it will not invent the missing detail. You will get a picture that looks slightly crisper but still soft. The honest fix in those cases is to use a better source photo. The same applies to a photo that has been compressed many times: the blocky artefacts are already baked in, and aggressive sharpening makes them more visible rather than less. For those images, a small amount of noise reduction followed by a modest sharpen gives the most natural result.

Exporting and file size

The enhanced photo is exported as a JPEG at high quality, and you can set a maximum file size in kilobytes if you need to upload it somewhere with a limit. Because sharpening adds high-frequency detail, a sharpened photo compresses less efficiently than the original, so the file will usually be slightly larger at the same quality setting. If you are preparing a photo for a form that accepts only a small file, sharpen first and then compress to the exact size using the compressor tool, rather than trying to do both at once.