Size60
Softness50
Strength100
Drop an image here, paste one, or open a file.
Your photo is edited on your device and never uploaded.
Zoom100
ModemixFree online mask editor
How to edit the saturation of part of a photo
- 1
Load your photo
Drag a photo onto the page, paste one from your clipboard, or click Open image. The file stays on your device.
- 2
Brush a mask over the area you want to change
Pick the Brush tool and paint over the region you want to adjust — a jacket, the sky, a face, one flower. Raise Softness for a feathered edge that blends invisibly, and lower Strength to apply the change at partial opacity.
- 3
Clean up the edges with the eraser
Switch to the Erase tool and brush over anything you painted by mistake. Press X at any time to show the mask in red so you can see exactly what is selected.
- 4
Adjust saturation and the other sliders
Move the Saturation slider to make the masked area more vivid or fully grayscale. Exposure, Contrast, Hue, and Warmth apply to the same masked area, so the rest of the photo is untouched.
- 5
Download the result
Click Download PNG to save the edited image at its original resolution, with no watermark.
Shortcuts
- Shift + drag
- Fine control on any slider (quarter speed)
- Double-click
- Reset a slider to its default
- B
- Brush — paint mask
- E
- Erase — remove mask
- X
- Show the mask as a red overlay
- [ ]
- Shrink or grow the brush
- ⌥ + scroll
- Brush size
- Pinch
- Zoom the image (not the page)
- Scroll / Space + drag
- Pan around a zoomed image
- ⌘Z / Ctrl+Z
- Undo the last stroke
Mask editor questions, answered
How do I change the saturation of only part of an image?
Paint a mask over the area you want to change, then move the saturation slider. The Modemix mask image editor applies every adjustment through the mask, so only the pixels you brushed are affected and the rest of the photo keeps its original colors. Painting with a soft brush feathers the boundary so the edit does not show a visible edge.
What is a mask in photo editing?
A mask is a grayscale selection that tells an editor where an adjustment applies. Where the mask is painted, the edit shows at full strength; where it is empty, the original photo shows through; partially painted areas blend the two. Masking is how Photoshop and Lightroom do local adjustments, and it is what the Modemix mask image editor does with a brush and an eraser.
Is this online mask editor free?
Yes. The Modemix mask image editor is completely free, requires no account or signup, and adds no watermark to exported images. There is no export limit and no paid tier.
Are my photos uploaded to a server?
No. The Modemix mask image editor runs entirely in your browser using the HTML canvas. Your image is never sent to Modemix or to any third party, and the exported PNG is generated on your own device.
Is this a free alternative to Lightroom?
For one specific job, yes. Lightroom's local adjustment brush lets you mask part of a photo and change the saturation, exposure, and contrast of only that area, and that is exactly what the Modemix mask image editor does — in a browser tab, with no install, no subscription, and no account. It is not a full Lightroom replacement: there is no RAW processing, no catalog, no presets, no tone curves, and no healing brush. If all you need is to change the color of one area of a JPEG or PNG, this does that job in about ten seconds.
Can I make a photo black and white except for one color or object?
Yes. Brush a mask over everything you want to stay in color, then drag the saturation slider down to zero with the mask inverted — or, more simply, mask the background and set saturation to 0 so only the unmasked subject keeps its color. This is the classic selective-color effect, and it takes about ten seconds in the Modemix mask image editor.
Does it work on a phone or tablet?
Yes. The Modemix mask image editor supports touch and stylus input, so you can paint a mask with your finger or an Apple Pencil on a phone or tablet, and it works the same way as with a mouse on a desktop.
What image formats can I edit?
Any image format your browser can open, including JPEG, PNG, WebP, GIF, and AVIF. Exports are always full-resolution PNG so the edit stays lossless.
Lightroom and Photoshop are trademarks of Adobe Inc. Modemix is not affiliated with, endorsed by, or sponsored by Adobe.
Your image never leaves your device
The Modemix mask image editor does all of its work inside your browser. When you open a photo, the file is read locally and drawn onto an HTML canvas on your own machine. The mask you paint, every slider you move, and the final PNG export are all computed there. Nothing is uploaded.
There is no server that receives your image, because there is no upload step at all. Modemix never sees your photo, never stores it, and never sends it to a third party. No account, no sign-in, and no email address is required to use the editor.
You can verify this yourself: open your browser's developer tools, switch to the Network tab, and edit a photo. No request carries your image. You can also disconnect from the internet once this page has loaded — the editor keeps working, because editing needs nothing from the network.
Your mask and adjustments are held in memory only. Closing or reloading the tab discards them, so the only copy of your edit is the PNG you choose to download.
Modemix does collect ordinary, aggregate page analytics for this website — how many people opened the page, and from where. That is about page visits, not about image content: your photos and masks are never part of it.