More often than not, we are unpleased with our image straight-out-of-the-camera (SOOC). As photographers, we need to edit them to emphasize the parts that make the photographs stand out.
Frequency separation is one way to do this. Read through our article here for what frequency separation is and how to use it.
What is Frequency Separation
Frequency separation breaks down image data into what we call ‘spatial frequencies’. You can then adjust these different frequencies independently.
There could be a number of different frequencies within each image. They all contain different amounts of information.
High frequencies in an image will contain information about the fine details. These include hair, skin tone, skin texture, pores, fine lines, and skin imperfections.
Low frequencies carry information about volume, tone and color transitions. Basically, shadows and light areas, colors and tones.
We use the frequency separation retouching mainly for skin retouching. There are many ways you can do this. You could use a High Pass filter, for example.
By using Gaussian blur instead, the spread and pixel radius are chosen for us.
Our method here is one of the fastest and easiest.
Why Use Frequency Separation
Look at the image below. We want to keep the texture of the mans’ face, as that is interesting and full of character.
We need to look below this to areas of blotchiness, or where the face doesn’t receive the same amount of light, contrast, color or otherwise.
How to Create Frequency Separation in Photoshop
First, open your image in Adobe Photoshop.
Duplicate the background layer three times. Do this by dragging the layer to the ‘Create a New Layer’ tab at the bottom.
Rename the different layers as you see fit, but we prefer High-Frequency Layer, Low-Frequency Layer, and Background.
The High-Frequency layer is for the texture, the Low-Frequency Layer is for shadows and light areas. The Background Layer allows you to revert back to the original if need be.
Next, turn off the High Frequency Layer. You can do this by clicking on the ‘eye’ icon next to the layer.
Select the Low Frequency Layer, go to Filter>Gaussian Blur.
In the pop-up dialogue box, select a radius value that puts the texture of the face just out of focus.
After pressing ‘OK’, make sure the High Frequency Layer is now turned on.
With it selected, go to Image>Apply Image.
In the Apply Image dialogue box, make sure the Layer says Low Frequency Layer. If you named the layers differently, make sure it is the one you applied the gaussian blur too.
Change the ‘Blending’ option to Subtract, and the ‘Scale’ and ‘Offset’ should be 2 and 128 respectively.
Press ‘Ok’. Next, change the blending option in the Layers panel to Linear Light.
This concludes how to make a frequency separation. Next, we will look at how to use it.
How to Use Frequency Separation
Ensure the Low Frequency Layer is selected.
Locate the Lasso tool on the toolbar on the left of the main window.
Start with the areas that have the highest concentration of blotchiness and an overabundance of texture.
Draw the lasso around the area.
Finish the selection by taking the end of the lasso back to where you started from.
For a better idea of the selection, use the Quick Mask Tool. Press ‘Q’.
You may find that the edges are a little too harsh. You can change this by increasing the amount of Feathering.
Press ‘Q’ to leave the Quick Mask Tool, where you can go to the top toolbar and change the Feather. Use 27 px.
Exit the Quick Mask Tool, then go to Filter>Gaussian Blur.
Change the Radius to a slightly blurred version. Somewhere around 4 pixels.
This will obviously change depending on the texture of the face you are working on.
Repeat this step for every area of blotchiness that you find.
Use different varying degrees of radius as not to make the editing process obvious.
Repeat as many times as you need to.
After you have finished, the face should have a difference such as this:
Next, select the top layer.
Find and select the Clone Stamp from the left-hand toolbar.
Ensure that the Sample you are using shows only This Layer.
With the clone stamp tool selected, press Alt to select a source zone, which will give you the texture for when you apply it (Alt to select a sample, release Alt to apply).
Go through-out the face, cloning and applying where you see fit on a more local scale.
Zoom in without changing your selected tool by holding Alt and using the middle mouse button.
And there we have it. Once you are finished, ensure to do a sweep to make sure you covered all of the areas.
If you feel the blur is too strong, you can bring down the opacity.
This will let the original background layer to come through a little more, increasing the texture as it was originally.
To do this, you need to select both layers, and then reduce the Opacity to around 80%, or as you feel.
There we have it. As you can see from the three images below, we have the original image, the finished result before we changed the opacity and the image after.
There are a few different ways you can create this frequency separation technique, but we found this to be the fastest and easiest to use.
Consider the Surface Blur Tool, or even the Sharpening Tool to bring back some of the texture.
Practise until you know it inside out, as this is a very helpful tool for all those of you who focus on portrait photography.