What is the Split Frequency Retouching method

After watching a French professional photographer explaining on Youtube how one should retouch portrait using Adobe Photoshop, I have decided to cover that topic once again. Why? Because following his method is the worse thing one photographer can do to a portrait once it has been shot.

My initial photo

Portrait that has not been edited

Portrait that has not been edited


His Method

Use the Gaussian Blur tool to hide all skin details and use the eraser tool to reveal the areas one wishes to keep sharp such as the eyes, the mouth, eyebrows, hair and the contour of the nose. Here is the result:

result of the bad portrait editing method described by the other photographer on youtube

the result of the bad portrait editing method described by the other photographer on youtube

My opinion

I think he forgot to mention that such method requires stepping away from the computer screen by about 5-10 meters to fully appreciate the benefits of such technique. Personally, i find the result worse than the original photograph.

I think he forgot to mention that such method requires stepping away from the computer screen by about 5-10 meters to fully appreciate the benefits of such technique. Personally, i find the result worse than the original photograph.


The Split Frequency Method

It is worth noting that while I am using a portrait photograph here to illustrate this method, once you understand how it works it can be applied to any photography. Nonetheless, this method has been widely used by photo retouchers for years now.

The concept

We consider two frequencies: The Low and the High.

  • The Low Frequency is all about the colour, highlights, tone of your image.
  • The High Frequency is all about the texture in your image: skin pores, hair, contours.

By creating a layer for each Frequency, one can modify either the texture without affecting the tone and vice versa. This avoids getting such a result when using the clone tool which not only changes the texture but the tone as well by cloning the source area onto the destination:

How to

First, duplicate twice your background layer. Here I called them High and Low to make it easier to understand:

layers in Photoshop

layers in Photoshop

While selecting the Low layer, go to Filter->Blur->Gaussian Blur…

The Gaussian Blur tool enable you to increase the details from the Low Frequency which subsequently hides the texture from the High Frequency. It is custom to use a value between 9 and 12 for 18-36Mb pixel images. The bigger the image to more pixels you will need to use.

Use of Gaussian Blur in Photoshop

Use of Gaussian Blur in Photoshop

Click Ok to apply the filter to the Low Layer.

While Selecting the High Layer, go to Image-> Apply Image…

If you work with 8b depth image:

Create the High Frequency layer in Photoshop for 8bit image

Create the High-Frequency layer in Photoshop for 8bit image

If you work with 16b depth image:

Create the High Frequency layer in Photoshop for 16bit image

Create the High-Frequency layer in Photoshop for 16bit image

As you can see, we now have only the texture from our image. Everything about the colour, the tone and highlight are not shown.

To work on the image, we are going to change the blending mode of our High-Frequency layer from Normal to Linear Light. You will notice that once done there is no difference between the resulting image (combination of the High and Low-Frequency layers) and the initial photograph. That is because all we did was splitting the image in two, separating the frequencies but they are both still there.

 Now you can simply select the High-Frequency layer and retouch any texture defect (hair, spot, scar…) or edit the Low-Frequency layer (or a transparent layer above it) to alter the colour, light and tone of the image without affection the texture.


Before & After

If we now compare the initial photo with the result (obtain during the recording of this video):

Original non edited photo

Original non-edited photo

After a 5 min retouch, using the Split Frequency Retouching method

After a 5 min retouch, using the Split Frequency Retouching method

Conclusion

There is not a unique solution to edit your photos whether it is a portrait or else. This episode is not about telling you what to do, but I value your faithful support over the years. When I watch a fellow pro photographer giving ridiculous advice to the photography Amateurs (meant as Photography lovers), I feel a certain responsibility to give my two cents on the subject.

I won’t hold the fishing pole for you but if I hear someone telling you to need to use a cork to catch a fish you can bet I will do my best to set the record straight.

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