Thursday, September 15, 2011


I have been very active in posting photos on Digital Photographer Philippines DPP this past few months and most of the photos I posted there is mostly beauty head shots that I retouch. I have noticed that quite a number of people there on the forum is really interested in learning the basic of digital high-end beauty retouching although I am quite surprise also to learn that this genre in Photoshop editing is somehow not so popular on DPP. 

I posted there few of my recent beauty head shot and the response was not bad I received some nice feedback from other members of the forum I even got some questions on my email asking me what sort of workflow I am using while other is asking how do I achieve a clean beauty head shot with skin texture still intact yet shiny soft skins are distinct. 

Well anyway I saw one thread there on that forum entitled Beauty Retouching and the thread got quite a number of posting and replies as well as workflow sharing and it was nice, I enjoy reading those stuff that they share some is really helpful and informative especially those that have a detailed workflow, but the rest is just for show-off nothing impressive, but anyway on that thread they mention the term "Frequency Separation" and how this applies to skin retouching. Now let me discuss this term in the best of my understanding and how this technique helps in getting a good result in beauty retouching.

Frequency separation in layman's term is simply splitting the image into two separate layers the high-frequency and low frequency, now why we need to split the image and how it helps in retouching.
Clone tool and Patch tool is the foremost tool in Photoshop that we often use when we want to remove blemishes on the skin, but one perplexity of every Photoshop user when utilizing such tools are after you clone or heal a certain area of the skin you will notice a shift in colors as well as a shift in highlights and shadows that are very visible on the image which tends to look blotchy specially if the skin has a lot of shadows. 

Say for example, you want to remove a pimple and you use the healing brush to remove the pimple so you sampled in an area of a skin around the pimple that is clear and you apply it on the affected area and right after you heal that portion you will notice that the skin tends to darken or sometime lighten compare to the other skin surrounding it and also the color becomes different thus creating blotches and the effect is very obvious. In short, every time we use a patch or clone tool or even other healing brush directly on an image there is always a tendency of shift in colors, shadows and in highlights. This always happen when the image has a very deep shadow and also when you heal an area along the edge of the face that has a transition of shadow and highlights.

Why does this thing occur? It is because these tools tend to copy not just the texture, but also the shadow and the highlights as well. 

So how to prevent this? Well that is where the Frequency Separation comes in.
Frequency separation or the "Split" is the technique being used by Retoucher to safely remove skin blemishes without the result of blotches or color shifts. In the split, the image are divided into two separate images, the first image contains the texture of the image and it is called the "high frequency" layer while the other image contains the colors, shadow and highlights and it is called the "low frequency" layer.
When you are on a Split you can safely heal the skin imperfection on the high frequency layer without the fear of color shifts, etc. because you are actually touching the texture part of the image. Now where is the color, shadow and highlights of the image? It is underneath the low frequency layer actually. 

Next I will try to write some article about Inverted High-Pass and what it can do on an Image.

Here are some link that discusses Frequency Separation" and how to do it in Photoshop:

Natalia Taffarel Blog 
Sean Baker Discussion about Frequency separation
Here's a very informative video tutorial from Angela

will add more links soon!

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