Features
Grayscale
Convert images to black-and-white using perceptually-weighted luminance: preserves transparency, avoids muddy average-of-RGB results.
What it does
The Grayscale tool converts a colour image to a single-channel monochrome version. There are several different ways to do this conversion and the wrong one produces noticeably worse results, so the tool defaults to the perceptually-correct option:
Luminance-weighted (Rec. 709): the default. Computes brightness as 0.2126·R + 0.7152·G + 0.0722·B. Matches how the human eye perceives brightness. Greens look bright, blues look dark, the result is balanced.
Alternative modes available:
- Average of RGB: simple
(R + G + B) / 3. Tends to look dark and muddy because it overweights blue (which the eye perceives as dim). - Lightness (HSL):
(max + min) / 2. Tends to wash out reds. - Channel pick: keep only one of R, G, or B. Useful for film-style monochrome (red channel gives lighter skies; green gives smoother skin; blue gives moody high-contrast).
- Desaturate to grey: preserves the original luminance per pixel but zeros the chroma. Equivalent to a "saturation = 0" filter pass.
Preserving transparency
The output keeps the full alpha channel of the source. A transparent PNG of a person in colour becomes a transparent PNG of a person in black-and-white, no white background introduced.
When grayscale is better than the BW filter preset
The Image Editor's filter presets include B&W, B&W Soft, and B&W Hard. Those are richer than this tool. They apply curves, grain, and toning on top of the grayscale conversion. Use them for finished cinematic black-and-white looks.
Use the Grayscale tool when you specifically need:
- A truly neutral grayscale conversion for documentation / scientific use.
- A monochrome version with no artistic adjustments at all.
- A quick way to remove colour from a logo without opening the editor.
Output format
You can save the result as PNG (lossless), WebP, or JPEG. The single-channel data is encoded as RGB with R=G=B for maximum compatibility. JPEG / PNG don't have a single-channel mode in the strict sense, but the resulting file is no larger than a true 1-channel encoding because the encoder collapses identical channels efficiently.
Privacy
Conversion happens in-browser. Files are never uploaded.
Related
- Image filters: B&W, Sepia, and Duotone presets
- Manual image adjustments
- Format converter
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