‘Blend If‘ is a highly undervalued tool in Photoshop. I use it on a daily basis for lots of different things and by the end of this article, you will too. I’m going to show the basics first, where to find it, how to use it, etc. Then we’ll move on to using it to apply some simple yet effective dodging and burning.
Where To Find ‘Blend If’ And How It Works
You can find Blend If by double clicking on any layer. When you do that the Layer Style dialog box will appear. On the very first screen (Blending Options), you’ll find the Blend If controls at the bottom. There are two gradients with pointers on either side. The top is labelled This Layer and the Underlying Layer.
The tool is pretty simple, but the effect it can have certainly isn’t. If you’re doing this on the computer, open an image in Photoshop and add an empty layer above the image. Fill this layer with black. The names of the two sliders are self-explanatory. The top slider, This Layer, will take the highlight/shadow analysis from only that single layer. Whereas, the Underlying Layer slider will take its analysis of the highlights and blacks from every layer beneath the one we are working on. As such, the majority of the time we use the Underlying Layer slider.
For those of you on the computer, click on one of the black pointers and drag it out. You’ll notice the black begins to disappear. The key point to note here is that it starts to disappear from the darkest area first. What you’re doing by moving that slider is telling the layer you are working on not to appear where ever the underlying layer is darker. If you were to slide the white (or grey) arrow, you would see the opposite happening.
One thing you may have noticed is that the transition is quite abrupt. If you were to paint on a layer now, you’d see some ugliness. That’s why we never slide the pointers as one. Hold Alt, click on the pointer and drag. By doing so, you’ll see the pointer split in half, and the effect have a smoother transition.
Down & Dirty Dodge And Burn Method
Hopefully, you now know that by moving these sliders you can tell the layer you’re working on to only be visible where the underlying layers are either brighter or darker. Now how do we use this? In the following image, I used this technique extensively. Effective dodging and burning is a laborious and skilled task. You need a really good understanding of light and the way it interacts with your scene to be able to realistically manipulate it. This is especially noticeable on a person’s face, for instance.
By using Blend If we can make this whole process a little easier. If you want to totally change the existing highlights and shadows in your image, then this technique will not work. Instead, what we will be doing is using Blend If to limit and control our brush work. Thus allowing us to a) extenuate the already existing highlights and shadows and b) be a little clumsy with our masks. Check out the before and after of this image I recently edited.
Pay special attention to the Stag, the trees and the mud pile the stag is standing on.
By using the Blend If technique I just explained, I was able to quickly carve out the highlights and shadows in the areas I just mentioned. I even used it to exaggerate the fog surrounding the stag a little. Take a look at the next photo that shows all the different dodge and burn layers I used. Note the symbol next to many of the layers. That symbol indicates that a layer style has been added (almost always that was Blend If).
If you are wondering how I dodge and burn in the first place, I opt for the curves method (there are lots to choose from). Create two curves layers, drag the curve up on one and down on the other, fill both layer masks with black and paint on those layers masks with a white brush. Simple. If you want to be a little more technical, I sometimes change the blend mode of those layers to Luminosity so as not to affect the colour of my image while dodging and burning.
What Else Could I Use This For?
In the most basic of terms, using Blend If is similar to using the brush tool in Lightroom to affect either the highlights, whites, shadows or blacks. The difference being that, in Photoshop, we can use layers, and apply this effect to more than just a dodging and burning layer.
I was recently editing this product shot for instance and needed to darken down the labels. Rather than make some complex selection, I just created a quick Burn layer and roughly painted over the labels. I then used Blend If to limit my selection to the labels and remove it from the white bottles.
There are so many possibilities for this technique, and I encourage you to mess around in Photoshop and see what you get. Good luck!