In this lecture, we will look at a professional
skin improvement technique,
called: 'Frequency separation'.
With Frequency separation
you can make skin look smoother,
without losing the texture of the skin.
The way this is done, is by splitting a layer
into two separate layers.
One of these layers will only have
the Color information,
and the other layer will only have
the Value information.
And it is on the Value layer,
where the skin 'texture' will be visible.
So if we smooth the skin, by blurring the Color layer,
we won't affect the skin texture.
In the texture, or Value layer,
we will improve the skin texture,
by removing texture irregularities,
with the Heal or Clone tool.
I have opened: 'Girl_Close-up'.
I start by duplicating the layer.
I name the duplicate: Color.
Now I will now blur the Color layer,
so we lose all texture.
The principle behind Frequency separation is,
that the detail we lose by blurring,
will be transported to the Value layer.
So from the Color layer, we're pushing the
detail out, to the Value layer.
I go to: Filters > Blur > Gaussian Blur.
So how much should I blur?
A good rule of thumb is to blur just enough,
until the blemishes have disappeared.
If you blur more than that,
which isn't needed,
you will also start to push out color
to the Value layer.
And for a good separation, we want to minimize
color in the Value layer.
I click on OK.
The Color layer is now ready.
Now let's create the Value layer.
Under Mode, I will choose: Grain extract.
What we are now seeing,
is going to be the Value layer.
There is almost no color, which is good.
Let's also have a look at the skin texture.
I zoom in to 200%.
I can see several texture irregularities,
that I can remove.
To create the actual Value layer, I right-click
on the Color layer, and choose: 'New from Visible'.
This will create a new layer
from what is visible at the moment.
I will name the new layer: Value.
I select the Color layer and set the blending
mode back to Normal.
Now I have a Value layer and a Color layer.
The last step, is to make these two layers
work together, as if they were one layer.
To do this, I will set the Value layer to:
Grain merge.
I will fit the image on screen
by pressing Ctrl-0.
By Shift-clicking on the original layer
I can toggle between seeing the original layer,
and the frequency separated layers.
As we can see,
visually, there is no difference.
Now let's start improving the skin.
I start with the Value layer.
I hide the original layer and the Color layer,
so I can work on the Value layer.
I will zoom in on the nose at 200%.
I will remove some irregularities.
I press 'J' to select the Heal tool.
In the Tool Options, I select a hard brush,
and set the size to 10.
I will not remove the freckles, but only focus
on the skin texture.
I will remove the lighter spots here,
and the darker spots here.
Let's have a look at the result.
As we can see, the skin texture
has become less irregular.
We could speed up this process
by using Heal selection.
It's a bit less precise,
but you can work much faster.
I press 'Q'
to enter Quick mask mode,
and at the bottom left, I right-click,
and I invert the mask.
I select the brush, and use a hard brush
at size 10.
I zoom to 300%.
I will click on the dark spots.
I press Q again to get a selection.
I go to: Filters > Enhance > Heal Selection.
I will set 'Context sampling' to 10 pixels,
and click on OK.
I press Ctrl-D to deselect.
Now, let's compare.
I have removed the dark spots.
To repeat Heal Selection quickly,
the next time I only have to press 'Ctrl-F'.
By pressing 'Ctrl-F', you automatically repeat
the last filter, with its last used settings.
Now let's go to the Color layer.
On the Color layer
I will smooth the color of the skin.
A convenient way to work,
is by using the Free select tool.
With the Free select tool, I will drag
several smaller selections, like this one.
After drawing a single selection,
I will blur the pixels inside that selection.
To prevent the blurring from being noticeable,
it is important that the selection has a soft edge.
I press 'Q'.
As we can see, right now
the selection has a hard edge.
I press 'Q' again.
I can smooth the hard edge of a selection
by going to: Select > Feather.
I will try 40 pixels, and click OK.
I press Q to see the result.
This is ok.
I press 'Q' again.
For drawing my next selection, I can
also set the feathering in the Tool options.
I activate 'Feather edges',
and drag 'Radius' to 40.
The next selection I draw,
will automatically have a feathered edge.
Because feathered an edge
will increase the size of the selection,
I will avoid coming to close to the edges
when I draw a selection.
I go to: Filters > Blur > Gaussian Blur.
If I click on Preview, I can see
the color of the skin is getting smoother.
I click on OK.
I press Ctrl-D to deselect.
Let's compare the before and after.
The skin has become smoother.
Let's repeat this at the right side.
I draw a selection.
By pressing Ctrl-F, I can repeat the
last used filter, without having to open the filter.
The last used value is still active.
So I drag a selection, press Ctrl-F,
drag a new selection,
and press Ctrl-F, and so on.
I Shift-click on the original layer to compare.
In the next lecture, we will look at a
powerful morphing tool for retouching,
called 'Warp Transform'.
