Photoshop has a built-in Mezzotint filter, but you probably won’t be pleased with the results. A more satisfactory approach involves performing a diffusion dither on each separate color channel. This method has three main steps: (1) Duplicate images are created, one for each color channel. (2) For each duplicate, a color channel is selected and the image is then converted to bitmap mode with diffusion dithering. (3) The color channels in the original image are replaced by their bitmap counterparts.

This mezzotint is an RGB image.Three copies of the original image were made—one for each color channel. (For CMYK images, four copies would have been required.)

Beginning with the first copy, the Channels Palette was opened and the Red channel selected. Then the color mode was changed from RGB to Bitmap. In the subsequent dialog box, Diffusion Dither was selected as the Method. The resultant image was copied to the clipboard. Next, in the original image, the Channels Palette was opened and its Red channel selected. The contents of the clipboard were then pasted into the Red channel.

The same procedure was then followed for the Green and Blue channels. After all three color channel had been replaced by their respective bitmap, diffusion-dithered counterparts, the RGB channel was selected and the result was the mezzotint effect shown here.