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Answer by Filipe for HTML5 Canvas Make Black Transparent

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You can accomplish that using blend modes.

Change the context globalCompositeOperation to screen, and you can get that result. Here's an example:

var canvas = document.getElementById("canvas");var context = canvas.getContext("2d");var image = new Image();image.src = "https://images.blogthings.com/thecolorfulpatterntest/pattern-4.png";image.onload = function() {  context.drawImage(image, 0, 0, canvas.width, canvas.height);  var blackImage = new Image();  blackImage.src="http://www.printmag.com/wp-content/uploads/Sillitoe-black-white.gif";  blackImage.onload = function(){    context.globalCompositeOperation = "screen";    context.drawImage(blackImage, 0, 0, canvas.width, canvas.height);  }};
<canvas id="canvas" width="300" height="250"></canvas><hr/><h1>Images used:</h1><img src="https://images.blogthings.com/thecolorfulpatterntest/pattern-4.png"/><img src="http://www.printmag.com/wp-content/uploads/Sillitoe-black-white.gif"/>

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