retocar imagem com requency separation

7/22/2019 Retocar imagem com requency separation

1/9

Software

Photohop CS2 or later

Time needed

1-2 hours

Skills

Learn a non-destructive

retouching workflow

Separate an image by

spatial frequencies

Recontour shadows and

highlights

Ben Secret explains how to achieve smooth yet sharp images, without losing realism

One of the black arts of photographic retouching is how to achieve the

impossibly smooth, yet sharply rendered skin, textures and fabrics seen

in fashion and beauty images. Photoshop has its own high quality

smoothing and sharpening filters, but the two processes tend to be

somewhat contradictory.

In this tutorial I'll walk you through how I retouch an image from start to

finish, using a technique that enables you to selectively process not only

different areas of an image, but also different detail levels. Frequency

separation involves creating a high detail (high spatial frequency) layer

and a low detail layer from a source image - a particularly clever methodof doing this was popularised by Sean Baker, a Maryland-based

photographer and retoucher. Using this technique enables you to smooth

and rework rough and fine details independently, and opens up some

very high-quality and non-destructive methods with which to sharpen your images.


2/9

01 In Photoshop, the first step is to ensure you're in 16-bit mode and, using your own photo, create two

duplicate layers of your source image. Name the middle layer 'low frequency' and the top 'high

frequency'. The bottom is your untouched image, which you may want to reference later.

02 Select the low frequency layer. To create your frequency separated image, you need to remove all

the detail from this layer. Select Gaussian Blur. The Radius setting determines the crossover point

between your high and low detail layers. This should be the point at which very fine details like skin

pores and eyelashes blur. Experiment until you're happy.


3/9

03 Now select the high frequency layer, and go to Image>Apply Image. For Layer, select Low frequency

from the drop-down menu, and for Blending, select Add (not Linear Dodge Add). Set Scale to 2, Offset

to 0, tick the Invert box and hit OK. All being well, you should now have a faint, fine detail layer. Change

the Blending Mode to Linear Light.

Advertisement

04 Your original image is now reconstructed with no loss in quality. Select the low frequency layer and

apply a surface blur (Filter>Blur). You want enough surface blur to smooth out any inconsistencies in

skin tone, without smudging highlights and shadows. I'm using Radius: 11, and Threshold: 10.


4/9

05 With your high frequency layer neatly separated, smoothing and painting on your image becomes

much less destructive. The light here has cast some hard shadows on the girl's face. Staying on the low

frequency layer, use the Eye Dropper and a soft paint brush with Flow set to 1% to smooth the contours

of the face.

06 Select the high frequency layer and clean up any blemishes, wrinkles and stray hairs. One of my

favourite tools is the Spot Healing Brush. Without the low frequencies, this tool becomes even more

effective, enabling you to zap unwanted details without then creating patchy colour inconsistencies.

07 This technique also enables you to apply some very high quality sharpening effects. Duplicate the


5/9

high frequency layer, add a mask to the new layer, copy and paste the high frequency image into its

own mask (Alt/Opt+click the Mask window in the Layers palette), and invert it (Ctrl/Cmd+I).

08 Next create a Dodge and Burn layer to bring out highlights and shadows where you want them. Go to

Layer>New> Layer, set the Mode to Overlay, and tick 'Fill with Overlay-neutral color (50% gray)'. Paint

on this layer with a soft black or white brush set to 1% Flow. (The image here demonstrates how this

layer looks with the Blending Mode set to Normal.)

09 Dodge and Burn can be used with large brushes to create dramatic highlights and shadows. I

created another Dodge and Burn layer for the background, and added some light to the image elements

I wanted to bring out, such as the cupcakes. I also created a little more glow from the light, and

darkened the shadows around the model.


6/9

10 After painting, dodging and burning the skin, it's not unusual to find small patchy areas and

inconsistencies in your brush work. To check for this, create a Curves adjustment layer with a veryexaggerated S-curve: small tonal inconsistencies will be blown up for easier correction.

11 Make your exaggerated curves layer invisible and create another Curves adjustment layer to pull the

shadows down a bit. Go to the Blue Channel and add some blue in the shadows. When I'm happy with

the outcome, I duplicate this layer so I can mix it in further, without having to change anything.


7/9

12 Now create another Curves adjustment layer to tweak the colour. For images that need heavy colour

correction, this would be one of the first steps in the retouching process. However, here it's more for a

creative effect. Select the Blue Channel and rotate the gradient clockwise by about 10 degrees.

13 Next add a Hue/Saturation layer and a Brightness/Contrast layer, just to balance the image at this

stage. Take the Saturation down to -27. When desaturating an image, I set the Blending Mode of the

Adjustment layer to Color so that I don't lose any contrast.

14 To add shine and specularity to the highlights, create a new layer and, with white selected as your

foreground colour, go to Select>Color Range. Take the Fuzziness up to a point where you can see only

the brightest highlights, hit OK, and then fill the selected area with white.


8/9

15 For this image I wanted

a softer, dream-like quality.

The white areas you just

filled might be quite grainy,

so with this layer selected,

add a Gaussian Blur with aRadius of about 5 pixels.

This will smooth the white

highlights on the skin and

add a subtle glow.

16 I also wanted to add some depth to the darker areas of the image, to make sure the focus is on the

model and the cupcakes. To do this, simply do the same thing again on a new layer, this time with black

selected as your foreground colour, and fill the area in black. Mix this in at a low Opacity, somewhere

around 10-20%.


9/9

17 Take a look at the image now: one thing dragging the eye away from the model's face and towards

the centre is the dark cupcake on the sink. To correct this, I created a new layer, set the Clone Stamp

tool to Sample: All Layers in the Tool Options bar, and replaced the dark cupcake with the yellow one

next to it.

18 When retouching, some creatives like to liquify an image as the first step but I prefer to leave it until

last as this is more of a destructive edit. I'll usually save the image as a Photoshop file, then flatten it forthis step. Here I made the nose straighter and reduced the stretch from the earring on the earlobe

retocar imagem com requency separation

Documents