Adjust curves online — bend a real tone curve to lift the shadows, hold the highlights and set the contrast of a photo exactly where you want it. PIXLFLW works entirely in your browser: your photo is processed locally and never uploaded to a server.
What you can do
- Point curve with any number of points — click to add a point, drag to bend the curve, double-click to remove it.
- Five channels — RGB for overall tone, Luma for brightness that keeps colors intact, and R, G and B for color grading.
- Histogram behind the curve — see where the tones of your photo actually sit while you drag.
- Presets to start from — contrast, soft contrast, faded film, matte, cross process, bright and moody.
How to adjust curves on a photo
- Drop an image into the upload area (formats: GIF, JPG, BMP, PNG, WEBP, HEIC, TIFF).
- Drag a point on the diagonal: up brightens the tones under it, down darkens them.
- Switch channels if you want to grade colors, then download as JPG or PNG.
What an S-curve does
The most useful move in a tone curve editor is the S: push the shadows a little further down, pull the highlights a little further up, and leave the mid-tone where it is. That adds contrast where the eye notices it without the washed-out look a plain brightness slider gives you. The opposite shape — lifting the black point and pulling the whites back — gives the faded, matte look of scanned film.
RGB, Luma and the color channels
The RGB tab bends all three channels at once, so it changes brightness and contrast together. The Luma tab changes brightness only: the luminance of every pixel is mapped through the curve and its red, green and blue are rescaled around it, so hue and saturation survive. The R, G and B tabs are where color grading happens — warm shadows and cool highlights, or a cross-processed look with red lifted and blue pulled down.
Curves are a non-destructive step — reopen the operation and move the points at any time before export, and the original file is never touched.