How is this different from a grayscale conversion?

Grayscale keeps up to 256 shades between black and white, preserving smooth tonal gradients. This tool is a hard threshold — every pixel becomes either pure black or pure white, with nothing in between, matching the classic '1-bit' black-and-white look.

How is the black/white split decided?

Each pixel's perceptual luminance is compared against an adjustable threshold (0-255, default 128); at or above becomes white, below becomes black. Raising the threshold makes more of the image turn black, and lowering it makes more turn white.

Is transparency preserved?

Alpha comes from the replacement color (both pure black and pure white default to fully opaque, alpha 255), not the source pixel's own alpha, so the result has no partial transparency.

Can I use a different threshold for high-contrast source images?

Yes — the threshold is fully adjustable, which matters a lot for this effect since the right cutoff point varies significantly depending on how bright or dark the original image is.

PNG to Black and White Converter

Overview

Introduction

'Black and white' technically means only two colors — pure black and pure white — not the many gray shades most people picture when they hear the phrase.

This tool produces that true, high-contrast threshold effect directly in your browser.

What Is PNG to Black and White Converter?

A pixel-level threshold converter that replaces every pixel with pure black or pure white based on its computed brightness, the same underlying operation as the more general PNG to Two Colors converter with its two output colors pinned to black and white.

The result is a stark, high-contrast, stencil-like image rather than a smooth continuous-tone one.

How PNG to Black and White Converter Works

For every pixel, perceptual luminance is computed using the standard weighted formula (green weighted most heavily, matching human brightness perception), then compared against the threshold value.

Pixels at or above the threshold become pure white; everything below becomes pure black — there's no interpolation or dithering, so the split is hard-edged.

When To Use PNG to Black and White Converter

Use it whenever you need a genuine two-tone black-and-white image — for a stencil, a high-contrast print, or a stylized graphic effect — rather than a smooth grayscale photo.

It's also useful for quickly visualizing which parts of an image are objectively brighter or darker than a given cutoff.

Often used alongside PNG to Two Colors Converter and PNG to Color Blocks Converter.

Features

Advantages

Runs entirely client-side; the uploaded image never leaves your browser.
Produces a genuinely flat, two-value result, ideal for stencils, laser engraving templates, or high-contrast print effects.
Adjustable threshold lets you tune exactly how much of the image falls into each color.

Limitations

All tonal and color detail beyond the black/white split is lost — this is a deliberately destructive, one-way effect.
A single global threshold can produce uneven results on images with strong local contrast variation, since it doesn't adapt per-region.

Examples

Portrait at default threshold

Input

A well-lit portrait photo, threshold 128

Output

A stark black-and-white silhouette-style image

The midpoint threshold works well for typically-exposed photos.

Dark photo needing adjustment

Input

An underexposed photo, threshold lowered to 80

Output

More of the image renders as white than it would at the default threshold

Lowering the threshold compensates for an overall darker source image.

Best Practices & Notes

Best Practices

Adjust the threshold based on your source image's overall brightness rather than assuming the default 128 always works well.
Use high-contrast, well-lit source photos for the most visually clean black-and-white result.

Developer Notes

convertPngToBlackAndWhite is a thin wrapper around png-to-two-colors-converter's convertPngToTwoColors, calling it with pure black and pure white pinned as the two output colors rather than re-deriving the same luminance-threshold math.