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Cloning and Healing

One of the most venerable, most practical tools in all of Photoshop is the clone stamp, which duplicates portions of an image. After selecting the tool — which you can do by pressing the S key — press the Alt key (or Option on the Mac) and click in the image window to specify the portion of the image you want to clone. This is termed the source point. Then paint with the tool to copy colors from that source point to another part of the image.

Closely related to the clone stamp tool is the healing brush, which clones multiple attributes of an image at a time. Press J to select the tool. Then, as with the clone stamp, Alt-click (or Option-click on the Mac) in the image to set the source of the clone. Note that the clone stamp and healing brush share a common source point, so setting the source for one tool sets it for both. Drag with the healing brush to mix the texture from the source point with the highlights, shadows, and colors of pixels that neighbor the brushstroke.

"Fascinating stuff," I hear you saying, "And by all means, I'll want you to elaborate. But why in the world would I want to clone pixels? I mean if these tools could clone, say, sheep, they'd be no-brainers. This weary world could always use a few more sheep. But pixels, I just don't get it." Clearly, if this is your first experience with cloning, it might sound peculiar. But as any dyed-in-the-wool Photoshop user will tell you, the clone stamp and healing brush are nothing short of invaluable for touching up images. You can remove dust, hairs, and other impurities; rebuild scratched, creased, or torn photographs; and even eliminate elements that wandered into your picture when you weren't looking. They are very simple, very useful tools.

The clone stamp tool

Let's start things off with a brief examination of the simpler of the two tools, the clone stamp. Although easy to use, it can be a little tricky at first. If you just start in dragging, Photoshop warns you that you must first define a source point. And it doesn't warn you politely. No "Sorry 'bout that," or "Ahem, pardon me, but . . . ." Just an abrupt, "Holy cow, you sorry excuse for a user! Don't you even know you have to Alt-click to define a source point to be used to repair the image? Honestly, get a grip or I'll shut down and bar you from ever launching me again!" or words to that effect. But while you may not like its tone, Photoshop's message is accurate. You have to set a source point before you can proceed.

How cloning works

Here's how it works: To clone part of an image, Alt-click (Option-click on the Mac) in the image window to specify a point of reference in the portion of the image you want to clone. Then click or drag with the tool in some other region of the image to paint a cloned spot or line. In Figure 7-2, for example, I pressed Alt (or Option) and clicked to the right of my sporty wife's head, as demonstrated by the appearance of the target cursor. I then painted the line shown on right. The stamp brush cursor shows the end of my drag; the clone source crosshair shows the corresponding point in the original image.

Figure 7-2: After Alt-clicking (Option-clicking on the Mac) at the point indicated by the target cursor, I dragged with the clone stamp tool to paint with the image. I painted inside a white area to make the brushstroke easier to see.

It's worth noting that the clone stamp clones the image as it existed before you began using the tool for as long as you hold down the mouse button. Even when you drag over an area that contains a clone, the tool references the original appearance of the image. This means there may be a visual disconnect between what the clone tool seems to be sourcing and what it paints, as illustrated in Figure 7-3. This is actually a good thing, however, because it avoids repetition of detail, a dead giveaway of poor retouching.

Figure 7-3: During the course of a single drag, the clone stamp tool continues to clone from the image as it appeared before you began painting. This prevents you from creating more than one clone during a single drag.

Figure 7-4: Here I used the clone stamp tool to merge my wife with a NASA photo. I employed the Multiply brush mode to achieve the shadowy edge. I also added some extra length to the snow-covered ground by cloning and recloning areas with the stamp tool. If you've ever seen The Honeymooners, you have to wonder, is this what Ralph Kramden had in mind?

Cloning options

When the clone stamp is active, the Options bar gives you access to the standard Brush, Mode, and Opacity settings that you get when using the brush tool. These permit you to mix the cloned image with the original to get different effects, as I explained at length in Chapter 5. You also get the Flow value and airbrush icon, which permit you to build up brushstrokes where they overlap and at points where you mouse down without moving the cursor.

You'll also find the Use All Layers check box, which lets you clone from multiple layers at a time, very useful for cloning from the composite image onto a new layer. For more information on this option, read the "Painting with the smudge tool" section of Chapter 5.

The only option associated with the stamp tool that's a complete departure from what we've seen so far is the Aligned check box, which locks down the relative source of a clone from one Alt- or Option-click to the next. To understand how this option works, think of the locations where you Alt-click (Option-click on the Mac) and begin dragging with the stamp tool as opposite ends of an imaginary straight line, as illustrated in Figure 7-5. When Aligned is turned on, the length and angle of this imaginary line remains fixed until the next time you Alt-click. As you drag, Photoshop moves the line, cloning pixels from one end of the line and laying them down at the other. The upshot is that regardless of how many times you start and stop dragging with the stamp tool, all brushstrokes match up as seamlessly as pieces in a puzzle.

Figure 7-5: Here I've set the stamp tool's blend mode to Hard Light to mix the moon image with the texture on the right. I've also turned on the Aligned check box to instruct Photoshop to clone the image continuously, no matter how many times I paint a new brushstroke.

If you want to clone from a single portion of an image repeatedly, deselect the Aligned check box. Figure 7-6 shows how, with Aligned turned off, Photoshop clones from the same point every time you paint a new line with the clone stamp tool. As a result, each of the brushstrokes features some fragment of my wife's face or hair but none line up with each other. In these examples, it may appear as if having Aligned selected is the superior setting. But as we'll see in later sections, both turning the option on and off serve specific purposes.

Figure 7-6: If you turn off the Aligned check box, Photoshop clones each new line from the point at which you Alt- or Option-click.

The healing brush

Photoshop 7 graced us with the mythical, magical, fantastical healing brush, and the world still collectively reels from the power it unleashed. I was first introduced to the healing brush in June 2001 at an Adobe-sponsored event called the Design Invitational. This was ten months before Photoshop 7 hit the shelves, and at the time, Adobe's plan was to introduce the healing brush as the central feature in the next bold upgrade to the software, the never released Photoshop 6.5. And to be honest, I was profoundly impressed. Finally, after 11 years cloning with the stamp tool, Adobe planned to release an upgrade that did more than simply duplicate pixels.

Naturally, the fellow who demoed the tool made it look like magic. The difference is that this time, magic isn't far from the truth. To get a feel for the tool, open a picture of a person's face that needs some work. For my part, I opened the picture shown in Figure 7-7. That's me, by the way, in case you were wondering what I look like. If not, my apologies — after all, you've done nothing to deserve such a gruesome image — but the picture well illustrates the healing brush because it suffers myriad irregularities, not the least of which is a field of divots emblazoned across my forehead. I can only guess that these scars were the result of a bombardment of very tiny meteorites. As suggested in Figure 7-8, my forehead and the surface of the moon bear too close a resemblance to be written off as pure chance.

Figure 7-7: I am told that this is a really good picture of me. As I'm sure you can understand, that depresses me to no end. Fortunately, I can make it appear a bit more human using the healing brush.

Figure 7-8: No, I didn't accidentally switch the labels on these two images. Hard as it is to believe, my forehead is indeed more dented than the lunar surface. You should see me when I sweat — my head illuminates the night sky.

If you can locate an image this hideous, God bless you. If not, hunt down something, say, half as bad. Select the healing brush by pressing the J key, which you can remember because it's the only letter missing from the words heal, patch, mend, fix, knit, remedy, salvage, cobble, requite, and the antonym wizen. Then press Alt (or Option) and click in the image to identify the texture that you want to match. Paint over a spot, scratch, pimple, wrinkle, or scar to miraculously heal that portion of the image. And it's fast, too. It took me about five minutes to retouch every defect on my forehead. As shown in Figure 7-9, the result is a virtual skin graft of newborn flesh, but without the cost or controversy.

Figure 7-9: Thanks to the healing brush, my once blemished brow is now the envy of men, women, and infants alike.

In case you can't get enough of watching me heal my own face — admittedly an act of vanity, but given the general state of my flesh, someone's got to do it — check out Color Plates 7-1 and 7-2. The former shows the healing brush and patch tool in action. The latter shows a bit of extra retouching performed the old-fashioned way, using any old tool in Photoshop's arsenal.

How healing works

In dabbling with the healing brush, you'll quickly discover two things. When it works, it works incredibly well, better than any other retouching technique available in Photoshop. But when it doesn't work, it really doesn't work, introducing colors and shades that appear clearly at odds with their surroundings. My experience is that, even when used carelessly, the tool produces desirable results slightly more often than it doesn't, so you may be content to paint and hope for the best. However, if you take a little time to learn what it is the healing brush is doing, you'll figure out how best to use it and when to use the clone stamp tool instead.

Naturally, I advocate the latter route, so with your approval, I'll take a moment and peel away some of the magic. The healing brush blends the pixels from the source point with the original pixels of your brushstroke. In that respect, it works a little bit like the clone stamp combined with a brush mode. But rather than blending two pixels at a time — cloned and underlying original, as a brush mode does — the healing brush blends cloned pixels with those just outside the brushstroke. The idea is that the pixels you're painting over are messed up, but the pixels just beyond the brushstroke are in good shape and should be emulated.

Figure 7-10 illustrates what I mean. Here we see what happens when I use the healing brush to clone a photo of my son onto the slightly embossed background shown on right. Notice also that the left edge of the background is shadowed while the right edge is lit. I applied a slight bevel to the brushstroke to make it easier to see. As the healing brush clones my son, it blends the colors from the photograph and embossed background in roughly equal amounts. This is a grayscale figure, so you'll have to take my word for that part, but this next part you can see for yourself: Photoshop dodges the brushstroke to match the light edges of the background and burns the brushstroke to match the dark edges. And it does all this according to the colors, highlights, and shadows that it encounters in tracing the very outer perimeter of the brushstroke, indicated by the dashed line on the right side of Figure 7-10.

Figure 7-10: Here I used the healing brush to clone my son (left) onto an embossed background (right). The dashed line on left shows the path of the source point throughout the brushstroke. The dashed line that surrounds the brushstroke on right indicates the outer edge of the brushstroke, which serves as the source for the additional coloring and shading that the healing brush performs.

Despite all this coloring and shading, bear in mind that the healing brush transfers the texture in its entirety from source point to brushstroke. In Figure 7-11, I Alt-clicked (Option-clicked) in the top image and dragged five times in the bottom image. In each case, the healing brush entirely replaced the pattern texture with my son's ear and eyes. At the same time, each brushstroke gets progressively darker to match the shade of the gradient in the background.

Figure 7-11: When set to the Normal brush mode, the healing brush clones the texture from the source image (above) in its entirety. The only thing that changes is the color and shade (bottom five strokes).

What can we deduce from this?

First, the healing brush replaces the texture as you paint just as surely as if you were using the clone stamp tool. If you want to mix textures, you'll need to employ a brush mode, as I explain in the next section.

TipSecond, the manner in which the color and shading are mixed is directly linked to the size and hardness of your brush. Bear in mind that Photoshop is looking at the outside edge of the brushstroke. As illustrated way back in Figure 5-19 (see Chapter 5), the outer edge of the brush grows as the Hardness value shrinks. So soft brushes cause the healing brush to factor in more surrounding colors and shading.

The upshot is that if a brushstroke seems the wrong color, or it's too dark or light, undo it. Then modify the brush size or hardness, usually by making it smaller or harder. And try again.

Healing options

In contrast to its astonishing editing powers, there's little you can do to customize the behavior of the healing brush. It permits you neither to use custom brushes nor to apply any of the settings in the Brushes palette. To modify a brush, you have to click the Brush icon in the Options bar. This gives you access to Photoshop-6-style brush tip settings along with a single dynamic, which lets you link brush size to pen pressure or airbrush wheel.

You have no control over Opacity or Flow. (It's a shocking omission, frankly, but you can work around this problem using Edit Fade, as I'll discuss later.) Meanwhile, the brush modes are limited to just eight. In each case, the mode merges cloned and original pixels, and then performs the additional healing blending. By way of example, Figure 7-12 shows five of the eight modes when painted over a horizontal gradient. Thanks to the dodging and burning applied by the healing brush, dark modes like Multiply and light modes such as Screen can be substantially compromised. In fact, truth be told, most of the brush modes have little effect.

Figure 7-12: Examples of the healing brush combined with five brush modes across a light-to-dark gradient. Due to Photoshop's healing algorithms, many portions of the Multiply brushstroke are lighter than those of the Screen stroke.

Other options include the Source buttons, which determine whether the healing brush clones pixels (Sampled) or paints with a predefined texture (Pattern). You also have the Aligned check box, which aligns multiple brushstrokes to a fixed source point, as described previously in the "Cloning options" section. The Aligned check boxes for the healing brush and clone stamp tools are linked, so selecting one selects the other as well.

The patch tool

If you prefer to heal a selected area all at once, choose the patch tool from the healing brush flyout menu in the toolbox. You can also press the J key — or if you did not turn off the Use Shift Key for Tool Switch check box in the Preferences dialog box, press Shift+J instead.

You can use the patch tool in one of two ways:

Define destination, drag onto source: Assuming the Source option is selected in the Options bar, as by default, use the patch tool to draw an outline around the portion of the image you want to heal. This creates a selection outline. In Figure 7-13, for example, I selected my eyes. Next, drag inside the selection outline to move it to a new location. The middle image in Figure 7-13 finds me dragging the selection over my forehead. The spot at which you release the mouse button determines the source for the clone. When I dropped the selection on my forehead, Photoshop healed the forehead onto my eyes, as the final image in the figure shows.

Figure 7-13: Armed with the patch tool, draw a selection outline around the portion of the image you want to heal (top), drag the selection over the clone source (middle), and release to watch the original selection heal away (bottom).

Define source, drag onto destination: If dragging the thing you want to heal onto the thing you want to clone seems backwards to you, flip it. Select the Destination radio button in the Options bar. Then use the patch tool to select the portion of the image that you want to clone. Drag the selection over the area you want to heal and release your mouse button.

Insofar as selecting is concerned, the patch tool behaves just like the standard lasso tool. You can add to a selection by Shift-dragging or delete by Alt-dragging (Option-dragging on the Mac). You can even soften a patch using Select Feather or modify it in the quick mask mode, thus giving the patch tool more room along the edge of the selection to sample colors and shades. And there's nothing that says you have to draw a selection with the patch tool. Feel free to define the selection any way you want, and then use the patch tool to move it over the source or destination area. For complete information on creating and editing selections, read Chapter 8.

The patch tool lacks Opacity and brush mode controls, and you can't use it between layers or between different images. All work has to be performed on a single layer, which ultimately limits its potential. On the plus side, you can patch a selection with a predefined pattern by clicking the Use Pattern button in the Options bar.