How to Use the ‘Blend If’ Tools in Photoshop

Photography Tips

Many handy Photoshop tools are either overlooked, misunderstood, or simply unknown, often because they lie tucked away as part of a larger palette or dialog box. The ‘Blend If’ slider is just one of those tools—incredibly easy to use and particularly helpful if you have dodge and burn as part of your workflow. Whether you’re new to Photoshop or an old hand, this tutorial from Photoshop master Aaron Nace will shed light on one of the lesser known tools in Photoshop:

What is the ‘Blend If’ Slider?

The “Blend If” slider is essentially an easy-to-use blending tool that allows you to blend based off of information from the layer you’re on, or based off of information from the rest of the image. It allows you to blend either from shadows or highlights. You can even choose your default colors (in RGB). Put simply, Blend If lets you blend two layers based on values of lightness and color. You can use it for everything from simplifying you dodge and burn workflow to removing an object from its background.

Key Aspects of Using the “Blend If’ Slider

• Feathering yields the most realistic outcomes. To feather, simply hold down the Option (or Alt) key. This separates the sliders and allows far more control over the degree and smoothness of blending.
• To enhance highlights, simply paint white over the area(s) where you’d like to add highlights, pull up the Blend If dialog box, and move the bottom slider from left to right to get the effect you’re looking for. (Remember to feather!) When you’re finished, change the blend mode to Soft Light.
• Enhancing the shadows is the same technique: create a new layer and paint black over the areas you’d like to enhance. Adjust the Blend If sliders to your liking and then change the blend mode to Soft Light. If needed, lower the opacity of the of the layer a bit.

The bottom line? The Blend If sliders allow you to blend layers without having to make complex selections, saving incredible amounts of time. They also allow for a level of easy experimentation that can result in some great effects, or as Nace puts it,

“When it comes to blending layers together, there really is no better tool. Combine the ‘blend if’ sliders with blending modes—you’re going to be amazed at what you can do.”