Make a Photo Black and White - Grayscale, Sepia, Duotone

Four different things people mean by "black and white"

Ask for a black and white photo and you could mean four very different images. Grayscale is what photographers mean: every shade from black to white, like a classic film print. Sepia is grayscale tinted warm brown, the look of a 1900s portrait. Threshold is literally only black and only white, no grays at all, which is what you need for a stencil, a vinyl cutter, a rubber stamp, a laser engraver or a crisp scanned signature. Duotone maps the shadows to one color and the highlights to another, the Spotify-poster look.

This tool does all four, with a live preview and full-resolution export. Pick the effect from the menu and the relevant sliders appear.

How to make a photo black and white

Choose an image. The default effect is grayscale using Rec. 709 luminance, so you'll see the black and white version immediately. Adjust brightness and contrast to taste, flip Show original to compare, then press Save full-size image and Download. The preview runs on a smaller copy so the sliders stay instant; the save re-runs the exact same math on every pixel of the original. JPG stays JPG, PNG and WebP stay as they are.

Strength blends the effect with the original color. At 100 percent it's full grayscale; at 60 percent you get the faded, muted look that's popular for editorial and wedding photos.

Why the gray conversion method matters

Converting color to gray isn't just averaging red, green and blue. Our eyes are far more sensitive to green than blue, so a plain average makes blue skies look too bright and green foliage too dark. The Rec. 709 luminance weights (21 percent red, 72 percent green, 7 percent blue) match how bright each color actually looks on a modern screen, which is why it's the default. Rec. 601 is the older TV standard with slightly more red; some people prefer its warmer skin tones.

The red and green filter options copy what black and white film photographers did with glass filters. A red filter darkens blue skies dramatically and makes clouds pop, the Ansel Adams landscape look. A green filter smooths skin and lightens foliage, which is flattering for portraits. Try each on the same photo; the difference is bigger than you'd expect.

Pure black and white for stencils, cutting and scans

Choose Pure black and white and every pixel becomes either black or white. The threshold slider sets the cut-off: pixels darker than the value go black, lighter go white. Start at 128 and move it until the lines you care about are solid and the background is clean. For a photographed signature or a handwritten note, push contrast up first and you'll get a scan-quality result from a phone photo.

Turn on Dither for photos. Instead of a hard cut, Floyd-Steinberg dithering spreads each pixel's error to its neighbours, so mid-tones become patterns of black dots, like a newspaper photo. That's what laser engravers, thermal receipt printers and e-ink displays need to show a photo with just two colors. Leave dithering off for logos, text and anything you'll cut on a Cricut or Silhouette; you want clean edges there, not dots.

Sepia and duotone

Sepia uses the standard sepia matrix, the same one CSS filters use, so the look matches what designers expect. Lower the strength to around 50 percent for a subtle warm vintage feel instead of a full antique print.

Duotone takes the grayscale brightness of each pixel and maps it between two colors you choose: shadow color for the darkest areas, highlight color for the brightest. Dark navy and warm yellow is the default; try your brand colors for a consistent set of social graphics, or deep purple and hot pink for a poster. Because it works on brightness, a high-contrast photo gives a much more striking duotone than a flat one, so bump contrast first.

Private by design

The image never leaves your device. All the pixel math runs in your browser, so it works on family photos, ID scans and client work without handing them to a server. Very large photos (think 50-megapixel camera files) can exceed a phone's canvas memory; if saving fails, shrink the image with the image resizer first. And if you only need part of the image, crop it before converting, since there are fewer pixels to process.