Macworld Masterclass: Making awkward selections in Photoshop

Exploring the limits of Selections and Masks in Photoshop

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  • bleirot DSC4247 Intro
  • mw psadv mask 01 1. A magnificent man...
  • mw psadv mask 02 2. Channels reveal differing contrasts
  • mw psadv mask 03 3. Duplicate a channel
  • mw psadv mask 04 4. Apply levels directly
  • mw psadv mask 05 5. Push the contrast
  • mw psadv mask 06 6. Burn it
  • mw psadv mask 07 7. Brush mode alternative
  • mw psadv mask 08 8. Dodging
  • mw psadv mask 09 9. Clean up the background
  • mw psadv mask 10 10. Make a channel selection
  • mw psadv mask 11 11. Check back to RGB
  • mw psadv mask 12 12. Refine edges
  • mw psadv mask 13 13. Make a layer mask
  • mw psadv mask 14 14. Urgh, fringes?
  • mw psadv mask 15 15. Paint through normal
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Intro

Extracting picture elements from photographs is a major reason creatives use Photoshop. Over the years Photoshop’s Selection and Masking Tools have matured; though, sadly, over time myths have propagated. Fables in portraiture include how hair can be selected from a busy detailed backgrounds. And the web is littered with how-to tutorials that just don’t cut it.

This tutorial doesn’t cover fresh ground. Rather it pulls together the most versatile photographic selection techniques and explores these processes. It also illustrates how Layer Blending Modes are essential in photo-composite work.

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Next Prev bleirot DSC4247

Extracting picture elements from photographs is a major reason creatives use Photoshop. Over the years Photoshop’s Selection and Masking Tools have matured; though, sadly, over time myths have propagated. Fables in portraiture include how hair can be selected from a busy detailed backgrounds. And the web is littered with how-to tutorials that just don’t cut it.

This tutorial doesn’t cover fresh ground. Rather it pulls together the most versatile photographic selection techniques and explores these processes. It also illustrates how Layer Blending Modes are essential in photo-composite work.

 

Step 2 of 16: 1. A magnificent man...

This photograph presents some real selection challenges. The background has a similar tone to the fine rigging and uncovered airframe; there are spokes in the wheels. We’re using Photoshop CS5 and the Essentials Workspace: Window > Workspace > Reset Essentials.

 

Step 3 of 16: 2. Channels reveal differing contrasts

In the Layers palette drag your first Layer to the Create New Layer icon to duplicate it. In Channels click on Red, Green and Blue (here the Red Channel is shown). Assess each Channel and note which has the greatest contrast between the object you want to select and its background.

 

Step 4 of 16: 3. Duplicate a channel

In this image the Blue Channel has the best contrast. In the Channels Palette drag the best channel to the Create New Channel icon, to the left of the Trash icon. There are several ways to duplicate a Channel, just like everything else in Photoshop. Now let’s make the duplicate Channel more contrasty.

 

Step 5 of 16: 4. Apply levels directly

Stay in the Channels Palette tab. Make sure you have your duplicated Channel selected. We now need to apply Levels directly to the new Channel. Adjustment Layers are the way to go for pretty much everything else in Photoshop, but not here. Go to the menu bar and choose Image > Levels.

 

Step 6 of 16: 5. Push the contrast

In Input Levels drag the White and Black Points about. Also move the mid point slider, aka Gamma, to the left and right, assessing which settings help isolate your object from its background. Curves can be used as an alternative to Levels, but only try Curves if you’re familiar with their foibles.

 

Step 7 of 16: 6. Burn it

There’s a limit to the contrast you can apply. The wings and fuselage are still grey. Use the Burn Tool, from the Tool Palette, to paint in the shape you hope to select. Burn Tool parameters include Highlights, Midtones and Shadows, there’s also Exposure. These can be set in the Tool Options bar.

 

Step 8 of 16: 7. Brush mode alternative

Dodge and Burn aren’t everyone’s favourites, though they’re much improved. Try the Brush Tool instead, with a soft edge. Set the Brush mode to Overlay, and with a solid black paint over the fine detail. We did this on the rigging to further enhance contrast. The brush was a little broader than the wires.

 

Step 9 of 16: 8. Dodging

With the positive area painted in solid black, turn your attention to the background. The Dodge Tool is useful; having the same parameters as the Burn Tool. Care is needed so that Exposure isn’t set so high that it immediately obliterates fine details such as the rigging. Undo or use History to recover any mistakes.

 

Step 10 of 16: 9. Clean up the background

Cleaning up a background can be a compromise. You may find that making the background a pure white around fine details dodges out too much. Leaving some areas light grey is OK. You’re making a mask. Pure black or white are solid masks, greys are semi-transparent. So, light grey is almost invisible.

 

Step 11 of 16: 10. Make a channel selection

Using a big, solid white brush we cleaned up the remaining background. To turn your efforts into a Selection drag your duplicate channel to the Load Channel As Selection icon. The marching-ants appear. Don’t worry if they don’t appear on the finest details of your image such as the rigging.

 

Step 12 of 16: 11. Check back to RGB

In the Channels Palette click on RGB to make the RGB channels active. With the marching ants still on the move, go to the Layers Palette. In Step 2 you should have made a duplicate of your first pixel layer, by default this will be called Background copy, make it active by clicking it.

 

Step 13 of 16: 12. Refine edges

From the Select menu, chose Refine Edge. From View Mode select Overlay. Use the Refine Radius Tool on fine details to see if you can improve your selection. Refine Edge can improve all kinds of selections. So far we’ve been preparing the ground so that Refine Edge has something solid to work with.

 

Step 14 of 16: 13. Make a layer mask

With the Background copy layer selected, press the Option key and hit the Add Layer Mask icon. Between the Background and Background copy make a new layer: click on Background, then click the Create New Layer icon. Paint this layer a solid colour. We chose green for the new background.

 

Step 15 of 16: 14. Urgh, fringes?

The masked image has pale fringes that look incongruous. To cure this we can use Layer Blending Modes. Choose the top layer and from the blending modes choose Multiply. The pale fringing disappears, but now the aeroplane is semi- transparent. Drag this layer to the Create New Layer icon to duplicate it.

 

Step 16 of 16: 15. Paint through normal

With the new top layer selected change its blending mode to Normal. Click on its mask. Using a soft brush paint through the mask of the Normal layer to reveal the Multiplied layer. We brushed over the rigging at differing brush opacities to create a convincing extraction of this flying machine.

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