Black & White Filter
Convert photos to greyscale, sepia or pure monochrome with luminance weighting.
Convert Photos to Black and White Properly
The naive way to make an image greyscale is to average the red, green and blue channels. It is also wrong. The eye is roughly twice as sensitive to green as to red and six times as sensitive to green as to blue, so an average makes reds too dark and greens too light — the reason amateur black-and-white conversions look muddy.
This converter uses the standard luminance weighting instead, and offers sepia, adjustable contrast and a pure two-tone threshold mode for when you want graphic rather than photographic results.
Key features
- Luminance-weighted greyscale — the correct conversion, matching how the eye actually responds to each channel.
- Sepia toning — warm monochrome without the flat, obviously-filtered look.
- Pure black and white — a threshold mode with an adjustable tipping point, for stencils, logos and high-contrast art.
- Contrast control — from 50% to 200%, applied after the conversion so highlights and shadows respond predictably.
- Side-by-side compare — toggle the original back on at any point.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Black & White Filter
- Add your photo
Drop it in; the greyscale preview appears immediately. - Choose a style
Luminance for a natural conversion, average for the classic flat look, sepia for warmth, or threshold for pure two-tone. - Adjust the contrast
Black and white lives or dies by contrast — push it until the image has real blacks and real whites. - Download the PNG
Save the converted copy at full resolution.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Media |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
Why does luminance look better than averaging?
Because human vision is not equally sensitive to each primary. Weighting green heavily and blue lightly reproduces the brightness relationships you actually perceive, so a red apple and green leaves keep their relative tones instead of collapsing together.
What is threshold mode for?
It forces every pixel to pure black or pure white with no grey between. That is what you need for stencils, screen-printing separations, laser cutting and high-contrast graphic work.
Can I get the colour back afterwards?
Not from the exported file — the colour information is genuinely discarded. Keep your original, which this tool never modifies.
Does it work on screenshots and documents?
Yes, and threshold mode in particular is excellent for cleaning up a photographed document into crisp readable black on white.