Software Secrets: Photoshop’s Hard Mix

If you’ve used Photoshop for any amount of time, chances are at one point or another you’ve found your way into the blending modes menu. There’s an overwhelming number of modes to choose from, and as you audition them one by one on your image, it can be unclear what a lot of them even do.

If you’ve followed tutorials to familiarize yourself with the software, you’re likely familiar with modes like multiply, screen and overlay, and for good reason. Not only are they extremely useful across a variety of applications, but their names describe their functions making them easy to remember. Other modes benefit from neither the former nor the latter.

Today let’s take a look at one of those modes. Taken from the Adobe site, Hard Mix’s functionality is described as:

Adds the red, green and blue channel values of the blend color to the RGB values of the base color. If the resulting sum for a channel is 255 or greater, it receives a value of 255; if less than 255, a value of 0. Therefore, all blended pixels have red, green, and blue channel values of either 0 or 255. This changes all pixels to primary additive colors (red, green, or blue), white, or black.

If that means as little to you as it does to me, then we would probably benefit from a visual aid. Let’s start with this image.

Next, we’ll add another layer over top and fill it with 50% grey, exactly halfway between black and white. We’ll set that layer’s blend mode to hard mix, and…

This is what we get. Pretty, right? Jokes aside, this does help to make some sense of the definition from Adobe.

Looking at the two images side by side, we can see that all pixels have in fact been changed into pure red, green, blue, white, or black. Interesting. From a more traditional photo editing standpoint, we can observe a couple of things. First, by reducing the pixels to only pure white or black, the image has become extremely high contrast. Second, because the colors have values of either 0 or 255, the image’s saturation has also been maxed out. In practical terms, Hard Mix is actually quite easy to understand. It simply boosts contrast and saturation. So if we just tone down the strength of the effect by reducing the fill…

Wow. A pretty usable image. Just as Adobe promised, the new image is higher contrast and more saturated. Through further experimentation, I’ve found that using color in place of grey for the fill layer can also yield interesting effects. It seems as though sticking to a color found naturally in the scene and leaning towards red, green or blue will produce a more natural result. For the image below I swapped the 50% grey for a green.

So what have we learned today? Maybe most importantly that the old platitude about not judging books by their covers is sometimes true. In regards to Hard Mix, however, we’ve learned that because of its all or nothing approach to color and saturation, it’s best to lower its fill and only use it in small amounts. When used tastefully, it can add an entirely new mood to a low contrast image by injecting it with a bit of drama.