Stamp Color Changer

Uploads a stamp PNG, decodes it onto an off-screen canvas, and replaces every pixel within a chosen color distance of a source hex color with a target hex color, leaving alpha untouched, then lets you download the recolored PNG. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-26

Overview

Introduction

This tool recolors a digital stamp's ink entirely client-side, letting you match a stamp graphic to a new brand color or document theme without reaching for a full image editor.

It works by tolerance-matching a source color, so it handles minor shading variation in scanned or photographed stamps, not just flat vector fills.

What Is Stamp Color Changer?

A client-side color-replacement tool built on Euclidean RGB distance matching, so a tolerance of 0 only matches an exact color while larger values catch anti-aliased or slightly-varied shades of the same ink.

It's the same recoloring operation used by this site's general PNG colors changer, applied to the stamp use case.

How Stamp Color Changer Works

Every pixel's RGB distance to your chosen source color is computed; pixels within the tolerance you set are replaced with the target color while their original alpha is preserved.

Pixels outside the tolerance band pass through completely unchanged, so backgrounds, transparency, and unrelated colors in the same image stay intact.

When To Use Stamp Color Changer

Use it to match a black ink stamp to a brand's accent color, or to recolor a seal or signature stamp for a themed document.

It's also useful for creating multiple color variants of the same stamp asset for different templates.

Features

Advantages

  • Runs entirely client-side; the uploaded stamp is never sent to a server.
  • A tolerance slider handles natural shading variation in scanned or photographed ink.
  • Alpha (transparency) is always preserved, so the stamp's silhouette stays intact.

Limitations

  • Only one source color is recolored per pass; multi-color stamps need multiple passes.
  • A tolerance set too low can leave a visible ring of the old color around anti-aliased edges.

Examples

Recolor black ink to brand blue

Input

A stamp with #000000 ink, change to #1D4ED8, tolerance 40

Output

The same stamp shape rendered in blue ink

A moderate tolerance catches the full range of near-black shading in a scanned stamp.

Swap a red seal for gold

Input

A stamp with #C0392B ink, change to #D4AF37, tolerance 60

Output

The seal rendered in a gold tone

A higher tolerance is needed because photographed red ink often varies more in hue and brightness.

Best Practices & Notes

Best Practices

  • Sample the stamp's actual ink color with an eyedropper before entering the 'change from' value for the most accurate match.
  • Preview at 100% before downloading to check for leftover fringing at edges.

Developer Notes

The color-distance replacement math lives in the shared png-colors-changer lib function; this tool's lib file is a thin, documented wrapper around it rather than a re-implementation.

Stamp Color Changer Use Cases

  • Matching a signature stamp to a company's brand palette
  • Producing colored variants of the same seal graphic
  • Recoloring a scanned rubber stamp impression for a themed template

Common Mistakes

  • Choosing a tolerance so high it also recolors unrelated dark shadows in the image.
  • Forgetting that only exact-format 6-digit hex colors are accepted for both the source and target.

Tips

  • Run the tool twice with different source/target pairs to recolor a two-tone stamp.
  • Combine with the black and white stamp creator first if you want a clean, uniform ink color to recolor from.

References

Frequently Asked Questions