Digital blending is a set of techniques that allow you to combine different versions of the same image (or different images) into one. The final image is created by revealing and hiding different parts of each layer. These techniques typically involve using layer masks and varying ways of manipulating them. However, there are also techniques that do not rely on masks at all.
In this article, you will learn a set of basic digital blending techniques that allow you to deal with most situations in which you need to blend layers.
A luminosity mask is a layer mask that hides a certain tonal range of your image while it reveals another tonal range. For example, the mask may be black where the highlights are and white where the shadows are to only reveal the shadow regions of your image. Since these masks are created directly from the tones in the image, the transitions between the black and white parts perfectly fit that image such that you can blend layers without introducing any of the typical artifacts like harsh edges or halos.
In this video, Greg Benz shows you how to create Luminosity Masks in Photoshop. This involves a rather complex series of steps, but there are tons of Photoshop actions out there that do this for you.
In this video, I am explaining to you how you can use such a set of luminosity masks to blend differently exposed images in Photoshop to get a balanced exposure and avoid highlight clipping and blocked-up shadows.
Many photographers use a graduated neutral density filter when they’re out in the field shooting. Essentially, that’s a piece of glass that is dark at the top and transparent at the bottom. It is put in front of your lens to darken the exposure in one area (typically the sky) while preserving the original exposure for the other areas.
There is a similar technique in Photoshop where you can create a layer mask for the same purpose. All you need is two differently exposed images (one exposed for the shadows and the other for the highlights). Then you can blend them using the Gradient tool as shown in the video below.
The Plain Brush Tool
The Brush tool is the most basic but also the most flexible tool to use for blending your images. You use the Brush to paint directly on your layer mask to reveal only certain parts of a specific layer and blend those with the rest of the image.
In this video, I show you the ins and outs of using the Brush tool for this type of blending work.
A technique that does not require any layer masks is the Blend if technique. Blend if is a tool found in the Layer Styles dialog box in Photoshop. It lets you define which tonal range of a layer is visible and which range is hidden to let the lower layer shine through. Similar to luminosity masks, this technique lets you blend image layers based on their brightness.