Grayscale Image

About the Grayscale Converter

This turns a colour photo into grayscale (shades of gray) or high-contrast pure black-and-white. Removing colour is a classic look for portraits and street photography, a way to standardise images for a document or print, or a step toward a stark two-tone graphic. An intensity control lets you go all the way to gray or only partly desaturate for a muted, faded-colour effect. However you spell it — grayscale or greyscale — it simply makes your picture grey.

Starting from an underexposed or flat-looking photo? Fixing that first with Brightness & Contrast often gives a cleaner grayscale result than converting the original.

How it works

The image is drawn to a canvas with a grayscale filter applied at the strength you set — 100% is fully gray, lower values leave some colour for a desaturated look. There's also an optional pure black-and-white mode: this takes each pixel's brightness (using the standard luminance weighting, where green counts most and blue least) and snaps it to either black or white at a mid-point threshold, producing a stark two-tone image with no grays. The result downloads as a PNG.

Assumptions and behaviour

• Grayscale intensity is adjustable from a subtle desaturation up to full gray.
• The optional black-and-white (threshold) mode converts to pure black and white using perceptual luminance (0.299 R + 0.587 G + 0.114 B), matching how the eye weights colours.
• Dimensions are unchanged; only colour is affected.
• Output is PNG.

Limitations

• Pure black-and-white mode uses a single fixed threshold, so very light or very dark photos can come out mostly white or mostly black — it doesn't offer an adjustable threshold or dithering for tonal detail.
• Grayscale is a colour operation only; it doesn't sharpen, adjust exposure, or add film-style toning (sepia, duotone).
• Output is PNG, so a grayscale photo won't be as small as a JPG — convert it to JPG or WebP or compress it afterwards if size matters.
• It can't recover detail that's lost in over- or under-exposed areas of the original.

Privacy

The conversion runs entirely in your browser with the Canvas API. Your image is never uploaded or stored.