Image Contrast Increaser
Increase or decrease contrast with one slider: give a flat photo its punch back, or soften a harsh one.
or browse filesdrop an image here or paste
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Increase or decrease contrast with one slider: give a flat photo its punch back, or soften a harsh one.
or browse filesdrop an image here or paste
Contrast is the distance between the dark parts of a picture and the bright parts. When it is too low the photo looks flat, grey and washed out; when it is too high the shadows block up into black and the highlights burn out to white. This tool puts that on one slider. Drag right to push the tones apart and give a dull image its punch back, drag left to pull them together and calm a harsh one, and the preview follows as you drag.
The slider runs from -100 to +100 and 0 is your original, untouched. At +100 every pixel sits twice as far from mid grey as it did; at -100 the whole picture collapses to flat grey. Most photos want something modest, somewhere between 10 and 35.
Drop a photo onto the page or paste one from the clipboard, then drag the slider until it looks right. Download as PNG for a lossless file, or JPG or WebP for a smaller one. Everything runs in your browser: the image is never uploaded, there is no signup, and no watermark is added.
Flat photos usually come from flat light. A shot taken on an overcast day, through glass, in haze or fog, or with a cheap phone camera in a dim room tends to land with all its tones bunched in the middle, and a modest push separates them again. Scans of old prints and photocopies respond well too, as do screenshots of faded documents where the text has gone grey.
The cost of pushing further is detail at the two ends. Once a dark area reaches pure black, everything that was in it becomes the same black and no amount of editing brings it back; the same happens to bright areas at pure white. That is why small amounts look good and large amounts look harsh. If you want to see where an image is already clipping before you start, the histogram viewer counts the pixels sitting at each end.
Turning contrast down is less common but genuinely useful. A photo destined to sit behind text on a poster, a slide or a web banner reads better when its tones are pulled together, because the text needs the contrast more than the picture does. Harsh midday photographs with black shadows and blown highlights soften into something more usable. Very low settings give the faded, washed-out look that suits a vintage or muted aesthetic.
The preview and the download run the same curve over the pixels, so what you see is what you save, at the full resolution of the file you loaded. Transparency is kept: a PNG with a transparent background stays transparent. All of it happens on your device through the canvas API, so no image is transmitted anywhere and the page keeps working offline once it has loaded.
For related colour work there is the image tinter to cast a photo toward a colour, the hue shifter to rotate its colours around the spectrum, and the black and white converter, which has a threshold mode for the extreme case of contrast with no grey at all.
Open the photo here and drag the slider to the right. The preview updates as you drag, so you can stop where it looks right rather than guessing at a number. Then download it as PNG, JPG or WebP at the original resolution. No account or upload is involved.
Each pixel is moved away from mid grey, or toward it, by the same proportion. A pixel that was already dark gets darker and a bright one gets brighter, while a pixel sitting exactly at mid grey does not move at all. Colours are not shifted, since all three channels take the same curve; only the spread between light and dark changes.
For most photos, between 10 and 35. Beyond that the darkest areas start turning into flat black and the brightest into flat white, and the detail in them is gone for good. Add it in small steps and watch the shadows: the moment they stop showing texture, you have gone too far.
Yes, drag the slider left of zero. The tones pull together and the image flattens, which is what you want behind text on a poster or a slide, or for a deliberately faded look. At -100 the picture becomes a single flat grey.
The change itself is applied at full resolution to every pixel of your original, so nothing is lost to scaling. What you cannot recover is detail pushed past pure black or pure white by a very high setting, so keep the original file if you might want to try a different amount later.
No. The image is decoded, adjusted and encoded in your browser, at preview and at full download resolution alike. Nothing is sent to any server, and the tool keeps working with the network disconnected once the page is open.