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ART141.tut_1 Sec2:54ART141.tut_1 Sec2:54 6/9/07 13:14:536/9/07 13:14:53

ON THE CD

TIME NEEDED

1-2 hours

SKILLS

• Defringing• Layer masks• Alpha channels• Adjustment layers

INFO

Justin Maller is a graphic artist from Melbourne,

Australia. He is currently working as a full-time freelance graphic artist, while creatively directing the crew over at http://depthcore.com. Check out his personal folio at http://superlover.com.au.

DEFRINGING HAIRSelecting fi ne strands of hair is one of the trickiest jobs in Photoshop, and it’s so hard to fi nd bald models. Here Justin Maller shows you some clever techniques for making accurate selections of complex subjects

3 Open up the Channels palette and fi nd which one presents the greatest

level of contrast between the model and the background. In this instance, the Blue channel presents the hair as the most solid block, so we’ll use this channel.

4 Duplicate the channel, and rename it ‘Alpha Mask’. Our aim here is to make

a mask of the model, with her in solid black and the background in white. Open the Levels dialog (Image>Adjustments>Levels).

2 Open Photoshop, and import model.jpg from this issue’s CD. As you can

see, the hair is quite complex here, and certainly can’t be extracted using the Pen tool or Magic Wand.

Accurately extracting models and their hair from a background is

one of the most irritating and time-consuming tasks a digital imager can be faced with – trying to make a smooth and detailed selection can leave you thumping the desk in frustration.

Making selections with the Pen tool can occasionally give you an adequate result, but it is virtually impossible to capture all of the fi ne strands and fl yaway hairs using this technique. Both the Magic Wand and the Magnetic Lasso selection tools are similarly ineffective, since most images do not have a universal selection tolerance that will enable you to wand out unwanted backdrops, and even if you do manage to walk the incredibly frustrating magnetic tightrope, the background will still be present in between hair strands, leaving you with annoying halos.

Fear not; lateral thinking reveals a relatively straightforward solution. The crux of this process lies in using channels to make a detailed alpha mask for your image (which will facilitate a similarly detailed selection), as well as in harnessing the Layer Matting features to refi ne your fi nal extraction. In this tutorial, we’ll guide you through this process, as well as show you some pre- and post-production tips to maximise the potential of your photos.

We’ll also explore the use of channels in post-production image retouching, and have a bit of fun balancing out our image with adjustment layers.

Tutorial and illustration by Justin Maller http://superlover.com.au

PHOTOSHOP

You’ll fi nd all the fi les you need for this tutorial in the folder marked Tutorials\Defringing on this issue’s CD.

5 The idea is to make the background as white as possible while defi ning

the edges of the hair as clearly as possible in black. Drag the shadows up a bit and the highlights much closer to the centre. Ignore the face and body; focus on the hair.

6 The next step is to make a selection of the rest of the model’s body. The

most precise way is to use the Pen tool; it handles basic shapes with the greatest accuracy, so zoom on in and start tracing.

October 2007 | 55

TUTORIAL |

1 If you plan to use your own photo here, make your life a bit easier by

shooting your models against the plainest background possible. In this shoot, I requested that the models lie on the simplest white sheet I could locate; blank walls will suffi ce as well.


| TUTORIAL

7 When you have completed your trace, right-click in the centre of the path

and select ‘Make Selection’ from the contextual menu. Ensure that the feather radius is set to 0 and click OK to make a live selection.

8 Fill your selection with solid black. It is important to make sure you have

100% Black as the fi ll, so ensure that the hex code is ‘00000’. After you have fi lled your selection, invert it (Ctrl+Shift+I).

9 Select a hard, medium-sized brush (around 100px) and start brushing the

background out with white. Take special care around the hair area – accuracy is important, but do not compromise the strands of hair you’ve defi ned.

10 Let’s see how our mask is looking on

the real thing. Re-enable the RGB channels (Ctrl+~), and turn on your Alpha Mask channel. Refi ne your mask as necessary; it should be quite accurate by this point.

12 With the selection active, return to the Layers palette, copy, then

paste to a new layer. Name the new layer ‘Model’. To get a clear read on how accurate your mask is, create a new layer and fi ll with white. Drag this behind the Model layer to see exactly what you have selected. If you aren’t happy, go back to step 4 and adjust your levels.

13 Let’s refi ne this selection a bit more. Bring up the Defringe dialog

(Layer>Matting>Defringe). Defringe this layer by 1.0px to clean it up a little and tidy the edges. You may wish to experiment with the White & Black Matte options, but they are too harsh in application here.

14 Now that we have successfully extracted and defringed our

model, let’s have a little more fun building the piece. Return to the Channels palette, and select the channel that offers the highest skin contrast. In this case it’s the Red channel. Duplicate it, and name the copy ‘Highlights’.

As this tutorial demonstrates, adjustment layers are powerful tools that should be used in nearly every composition to help balance and unite disparate objects and mediums. Like normal layers, adjustment layers can have a variety of blending modes, and it is well worth your time to experiment. After completing this tutorial, try setting the Gradient Map adjustment layer to Multiply or Linear Burn for some highly stylised results.

ADJUSTMENT LAYER MODES

For models with less complicated hair outlines, the Extract fi lter (Filter>Extract) may give you a satisfactory result. Simply use the Edge Highlighter brush to outline your fi gure, and fi ll the trace with the Fill Tool. Extract’s Smart Highlighting function will help you to make a more accurate highlight. Preview your extraction before hitting OK; you can use the Edge Touchup tool to refi ne the edges, or the Cleanup tool to remove extraneous background.

EXTRACT

56 | October 2007

PHOTOSHOP

11 Once you are satisfi ed with your mask, hide the visibility of the

Alpha Mask channel, then Ctrl-click on it to turn it into a selection. You will need to invert this selection again so that the model is selected. For a slightly smoother result, feather (Ctrl+Alt+D) the selection by 1px. You may also smooth the selection (Select>Modify>Smooth) by 1px.


TUTORIAL |

18 Open up objects.psd from the CD, and import each object into the

composition as its own layer. Arrange them as you see fi t; try to get a nice fl owering arrangement happening.

19 Ctrl-click an object layer to turn it into a selection. Fill with black in a

new layer, and position slightly down and to the right. Apply a mild Gaussian Blur, and reduce opacity to around 60 per cent. Repeat for each object and the main fi gure varying opacity as you go to add depth.

15 Back in the Layers palette, Ctrl-click your Model layer to turn it into a selection. With the selection active, return to

Channels, and copy your selection. Back to Layers, paste into a new layer; add a layer mask, and remove all hair from this layer.

16 Name the layer ‘Highlights’ to match its channel. Set the Layer

Mode to Color Dodge and the opacity to around 80 per cent; this should give you a smooth high-contrast effect with no loss in quality. This is an effective technique for performing quick skin touch-ups in everyday work.

17 Drag out a white-to-peach circular gradient in the background; you’ll

fi nd that virtually any background is more forgiving than stark black or white. Mix this one up a bit by using a Channel Mixer adjustment layer – tweak the Blue contrast down a bit, and apply a horizontal gradient Layer Mask.

20 Time to start balancing these elements out. Add a Color

Balance adjustment layer. Tweak the shadows towards Blue (+21), Magenta (-22) and Cyan (-12). Leave the midtones be, and drag the highlights to Yellow (-10).

21 Next, let’s get our desired level of contrast happening by applying a

Levels adjustment layer. If you set the Input Levels to 20, 1.27, 231, you should see the shadows deepen and highlights increase without losing much detail in the main composition.

22 Lastly apply a Gradient Map adjustment layer. This layer will unite our palette and fi nish off our piece. Create a gradient that progresses from Teal (#1AA4B4

at 0 per cent) to Lavender (#BE6BA7 at 50 per cent) to Yellow (#FFED50 at 100 per cent). Set the adjustment layer mode to Overlay and sit back to admire a job well done.

LAYER SETS

While completing this tutorial, try organising each set of elements into its own Layer Set. This project can be easily divided into fi ve different sets: Background, Shadows, Objects, Model and Adjustment Layers. It can make an enormous difference having these sets established while editing and refi ning your image: it makes layers easier to fi nd (especially if they are labelled), and the ability to switch an entire Layer Set’s visibility off makes precision editing of original elements much simpler. Like layers and adjustment layers, Layer Sets can also have blending modes – experimentation may yield surprising results!

October 2007 | 57


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