Frequency Separation has been around for a long time but has received a bad reputation in the past. This is not because there is anything wrong with the software. It’s simply because it was used incorrectly by some and taken too far by others.
The purpose of this Adobe tool is to remove any unwanted flaws from skin while keeping it looking natural. However, when people take the flawless part too far, the skin texture ends up looking like plastic because the detail is lost. The trick to using it successfully comes down to the techniques you apply.
The Frequency Separation process is done by separating the detail and texture from the tone and colour of the image, so they can be edited separately. Doing this makes it easier to preserve the details when performing intricate edits, while giving you meticulous control over the tones and colours. Here’s how it’s done:
To begin the process, open the image file in Photoshop and type Cmd/Ctrl-J to duplicate the Background layer.
This layer will be first in the layer stack and will be the high frequency layer. Name it “Detail & Texture”, then click on the visibility icon (the eye) to turn off its visibility for now.
This layer will be the low frequency layer. Change the name to “Colour & Tone”, right-click on it and select the Convert to Smart Object option.
To lightly blur the finer details, apply Gaussian Blur from the Filter menu (Radius: 2 Pixels should be fine).
Create a new blank layer before the Colour & Tone layer by typing CMD/Ctrl-Shift-N and call it “Retouch Colour & Tone”.
Detail & Texture layer:
Click the visibility icon of the Detail & Texure layer, select Image > Apply Image to set the layer. (Blending: Subtract, Scale: 2, Offset: 128). Click OK. Now you should have a grey image.
At the top left of the Layers palette, change the blending mode from Normal to “Linear Light”. This will change the grey image back to normal.
Colour & Tone (low frequency) Retouching:
Select your Retouch Colour & Tone layer and use the Healing Brush or Clone Stamp tool for brushing over blotches and wrinkles. (Note: In the Tools Option Bar, set the Sample field to Current & Below to ensure that no pixel information is selected from the top layer.)
Detail & Texture (high frequency) Retouching:
Select your Detail & Texture layer. It’s important that you set the Sample field, in the Tools Option Bar, to Current this time. Now you can remove any unwanted details such as blemishes, rough skin textures, blackheads, stray hairs, and so forth, and use the Clone Stamp tool (set Opacity and Flow to 100%) to clone the detail back into these areas.
The ultimate aim of portrait photography is to bring about the true essence of the person being photographed. This is why toning down wrinkles and removing distractions like temporary imperfections is so important. Adobe Photoshop Frequency Separation is the perfect, stream-line tool to achieve this, because it enables users to retouch skin in images faster, without compromising on quality.