This is a technique for modestly and attractively increasing contrast in an image. The goal is to understand why and how one uses a Lab equalization with the soft light blending mode at low opacity.
- [Instructor] Let's get started with using Lab in Photoshop. One of the simplest but still very powerful things you can do is to use an all channel Lab equalization along with soft light blending mode to add contrast to an image. Here's how this works. The other day I shot an image that you can see on the screen of an old pair of my eyeglasses. This image, like most, starts out in RGB. My first step is to create a copy of the image by selecting Duplicate from the Image menu. Next, with the duplicate copy active, I'll go ahead and covert it from RGB color to Lab by choosing Image, Mode, Lab color. You can now verify that the image is in Lab by looking at the title bar and also looking at the Channels palette where you can see the three Lab channels. With all three channels selected in the channel bar, choose Image, Adjustments, Equalize, which is at the bottom of the Adjustments menu to equalize the image. Equalize is a Photoshop adjustment that takes one or more channels to the extremes. So like colors become lighter, dark colors become darker, reds become redder, and so on. As you can see on the screen, the three channel equalization of the glasses image really makes a difference. You can't miss it, look at it side by side with the original, it's become this sort of grayed out, almost silhouette of the original image. Next, we're going to convert the duplicate image back from Lab to RGB. To do this, choose Image, Mode, RGB Color. Now I want to take the equalized duplicate and make it a layer of my original image. To do this, I will choose the Move tool, hold down the shift key, and drag the duplicate over the original, letting go of the mouse before I let go of the shift key, like that. So once again, I hold down the shift key, I use the Move tool, I drag the duplicate over the original, and I let go of the mouse. This is a constrained drop that creates exactly aligned layers, one on top of the other. If you do have trouble with it, you can alternatively take the original image, go Select, All, go Edit, Copy, move over to where you want to drop it, and go Edit, Paste, and that will have exactly the same effect. You can see the equalized version as the top of this layers stack in the Layers panel. I'm changing it to equalized, and I'm also going to make it a little bigger so you can see what happens when I change the blending mode to Soft Light. As you can see, this is a pretty attractive effect, but it can be a bit over the top. So I recommend taking the opacity of the equalized layer down to the 20 to 40% range. To do this, move the Opacity slider in the Layers panel to about 30%, like that. To summarize, we started with an image that needed some help smoothing out it's contrast. We made a duplicate image, converted to duplicate to Lab, applied an equalization adjustment to all three Lab channels, and then converted the duplicate image back to the RGB color space. After copying the equalized image over the original image, we set the blending mode to soft light and the opacity to an attractive level, and you can see the changes that happened by turning the equalized layer off and on. So here's where the image started, and here's what the equalization adjustment did to it to make it both sharper, but not in an unattractive way. This is a simple series of steps that can be accomplished very quickly and will improve almost any image. You can check this out on the sample image that I've provided, by why not pull up one of your own special images and see how well it works on almost any image?
- Converting images to Lab Color space
- Applying Curves to Lab channels
- Selective sharpening
- Inverting channels
- Making per-channel equalizations
- Using the Lab action
- Combining Lab Color with blending modes
- Making patterns with Lab images