黑白濾鏡

How to use

1. 1. Drop your image onto the upload zone or tap to select from your device.
2. 2. Select a conversion algorithm (luminosity is recommended for portraits and landscapes).
3. 3. Choose output format and quality.
4. 4. Click "Convert B&W" to process.
5. 5. Download the black-and-white image.

常見問題

What is the difference between the three algorithms?

Luminosity: 21% red + 72% green + 7% blue — matches human colour perception. Average: equal 33% each — simpler, flatter. Desaturate: (max + min channel) / 2 — based on HSL lightness, different tonal rendering.

Which algorithm should I use for portraits?

Luminosity produces the most natural portrait tones — skin renders at a pleasing mid-grey, eyes appear expressive. For high-key or very bright portraits, average can produce flatter, cleaner results.

Which algorithm is best for landscapes?

Luminosity makes blue skies dark and dramatic while keeping foliage and green areas lighter — classic film photography look. Desaturate produces a different, sometimes more even result on landscapes.

Is it lossless to convert to black and white?

The conversion itself is lossless in terms of tonal information. However, colour information is permanently lost. If you might want the colour version later, keep the original.

Can I combine B&W with sepia tone?

Yes — convert to B&W first with this tool, then run the result through the Sepia Filter tool. Starting from a clean B&W image produces the most authentic sepia-toned result.

What does "desaturate" mean?

Desaturate removes all colour saturation from an image, reducing it to greyscale based on HSL (Hue-Saturation-Lightness) lightness values. This is mathematically different from luminosity and produces a distinct tonal rendering.