Convert colour images to grayscale or pure black and white with three conversion modes — Luminance (perceptual), Average, and Desaturation. Includes contrast control, before/after preview, and bulk batch processing with ZIP download.
Drag and drop one or more colour images (JPG, PNG, WebP) into the upload zone. Bulk mode lets you queue up to 20 images and apply the same conversion settings to all of them in one click.
Select Luminance (perceptual, most natural for photos), Average (equal RGB weighting, flatter look), or Desaturation (midpoint of min/max channels). Optionally boost contrast with the slider to create a punchy black and white look.
Use the Before/After comparison slider to see the colour original beside the converted version. Download as JPG, PNG, or WebP. In bulk mode, Download All creates a ZIP of all converted images.
Luminance mode (also called BT.601 or perceptual) uses the formula 0.299R + 0.587G + 0.114B — weighting green heavily because human eyes are most sensitive to green light. This produces the most natural-looking grayscale for photographs. Average mode takes (R+G+B)/3, giving equal weight to all channels — producing a flatter, slightly washed-out look useful for stylised effects. Desaturation mode takes the midpoint between the minimum and maximum channel values, producing high-contrast results that emphasise colour differences.
Human vision is far more sensitive to green wavelengths than red or blue. The Luminance formula reflects this physiological fact — it gives green 59% of the weight, red 30%, and blue only 11%. This means grass, foliage, and skin tones translate to natural-looking gray values. If you used equal weights (Average mode), blue skies would appear too bright and red subjects too dark, resulting in an unrealistic grayscale.
Convert using Luminance or Desaturation mode, then increase the contrast slider to 50–80. This pushes mid-tones toward white or black, creating a more dramatic black and white effect. For true binary black and white (no gray tones), a threshold filter is needed — this tool produces grayscale (256 shades of gray) which is the most useful for photography.
Yes — pixel dimensions are preserved exactly. The grayscale conversion only changes the colour information in each pixel, not the number of pixels. Quality depends on your chosen output format: PNG is lossless; JPEG quality is set to 92% by default, preserving excellent detail. WebP provides the best quality-to-file-size ratio.
Yes — the bulk mode processes up to 20 images with the same conversion settings applied to all. All converted images are packaged into a single ZIP download, so you can convert a whole folder of product photos or portraits in one operation.
If you save a grayscale image as JPEG and reopen it, some viewers may show a very subtle colour cast from JPEG chroma subsampling. This tool produces true RGB grayscale (R=G=B for each pixel), which is compatible with all image viewers. If you need a true single-channel grayscale (smaller file, no chroma at all), download as PNG which preserves the exact pixel values without compression artifacts.
