Moving the mouse over the Preview pane changes the cursor to a hand. Dragging with this hand cursor pans the preview image within the pane. The buttons and pop-up menu at the bottom of the Preview pane are used to zoom in, zoom out, and select a specific zoom percentage. The pop-up menu also includes an Actual Pixels option, which displays the image at its actual size of 100%; a Fit in View option, which zooms the image so the entire image is visible in the Preview pane; and a Fit on Screen option, which maximizes the Filter Gallery to fill the entire screen.

Clicking the Show/Hide button in the top-left corner of the Settings pane hides the filter thumbnails and uses that space to increase the size of the Preview pane, as shown in Figure 13.2.

Figure 13.2. Clicking the Show/Hide button increases the size of the Preview pane by hiding all the filter thumbnails.

The Filter pane is organized into several different categories of filters including Artistic, Brush Strokes, Distort, Sketch, Stylize, and Texture. Similar categories are found in the Filter menu. The category that includes the current selected filter is highlighted in bold.

Clicking the small arrow to the left of the filter category name expands the category to reveal all the filters within that category. Clicking on filter thumbnail selects the filter and displays all its settings in the Settings pane. The selected filter's name is displayed at the top of the interface along with the zoom percentage, and the background of its thumbnail is highlighted dark gray.

The Settings pane includes a drop-down list of all the filters. Filters may be selected from this list when the filter thumbnails are hidden. Below this list, the settings for the current selected filter are displayed. Changing any of these settings alters the effects of the filter, and the Preview pane shows the changes.

At the bottom of the Settings pane is a list of filters applied to the preview listed in the order in which they are applied to the image. If you click a new filter, it replaces the currently selected filter. To apply an additional filter to the image, click the New Effect Layer button at the bottom of the Settings pane. This freezes the current selection and adds a new filter layer to the interface. The name of this filter layer is that of the filter that was applied.

If you click the Visibility icon to the left of the filter layer name to toggle it off, the Preview pane is updated to show the image without the filter. Selecting the filter layer and clicking the Delete Effect Layer button at the bottom of the Settings pane deletes filter layers.

If multiple filter layers exist in the Filter Galley, you can rearrange them by dragging one layer above or below another. Changing the order in which filters are applied can drastically change the resulting image.

When you're satisfied with the resulting preview, click OK to apply the listed filter layers to the image. Click Cancel to exit the Filter Gallery without applying any filters.

STEPS: Using the Photoshop Filter Gallery

The Filter

The first three Blur filters—Average, Blur, and Blur More—are applied without a dialog box. Average takes the average of all the selected colors and applies that average color to the entire selection. The Average filter is useful when used with the Magic Wand tool to create a single area with a single color.

The Blur filter removes any noise along hard edges by averaging the colors along these hard edges, resulting in a smoother overall image. The Blur More filter does the same but to a greater extent.

The Box Blur filter blurs the selected area by taking the average color value of pixels within a square area. The Radius value determines the size of the box.

The Gaussian Blur filter opens a dialog box where you can specify the amount of blur to add to the image. The Radius value determines the size of the groups of pixels that are averaged.

The Lens Blur filter opens a dialog box, shown in Figure 13.7, that lets you simulate a depth-of-field effect where the camera is focused on a particular point in the scene and all objects farther or nearer than that point are blurred in relationship to their distance from the focal point.

Figure 13.7. The Lens Blur dialog box includes a Preview pane.

The Source field lets you base the focal point on the image's Transparency value or an included Depth Mask. The Iris Shape field lets you choose the shape of the defined averaged areas where the blur is applied as well as its Blade Curvature and Rotation. You also can specify values for Specular Highlights and Noise.

The Motion and Radial Blur filters let you control the direction of the blur lines. The Motion Blur filter specifies an Angle and a Distance value to blur the image linearly, as shown in Figure 13.8. The Radial Blur filter blurs the image in concentric circles about a point that you can select in the Radial Blur dialog box, also shown in Figure 13.8.

The Shape Blur filter blurs the image using a selected shape. The Shape Blur dialog box, shown in Figure 13.9, includes several default options, but you can load new shapes using the pop-up menu. The Radius setting determines the size of the shape that blurs the image. Notice in the figure how the circular shape causes details in the image to be blurred in circular patterns.

Figure 13.8. The Motion Blur and Radial Blur dialog boxes let you blur the image using linear or radial lines.

Figure 13.9. The Shape Blur dialog box blurs areas using a selected shape.

The Smart Blur filter is unique in that it lets you blur areas of similar colored pixels based on the Threshold value. The Mode may be set to Normal, Edge Only, or Overlay Edge. The Edge Only and Overlay Edge options color the edges white based on the Threshold value. Figure 13.10 shows the Smart Blur dialog box. In the Preview pane, similar areas have been blended together.

Figure 13.10. The Smart Blur dialog box blurs local areas of similar pixels.

You can use the Surface Blur filter to blur the image while preserving its edges. This has the effect of softening the entire image while maintaining the image details. The larger the Radius setting, the more that the pixels bleed into one another and the Threshold value sets the limit for edges that are blurred. Figure 13.11 shows the Surface Blur dialog box.

Figure 13.11. The Surface Blur dialog box blurs the image while preserving its edges.

STEPS: Blurring an Image's Background

The Filter Gallery interface includes three filters in its Distort category, but the Filter

The Displace filter distorts the image based on a loaded displacement map. The displacement map defines how the pixels move, with black areas marking a negative displacement and white areas marking a positive displacement. Figure 13.14 shows a patterned image with the Displace filter applied using the simple displacement map.

Note

The Lens Correction filter, found in the Filter

The remaining Distort filters all open a dialog box where you can enter the amount of distortion to apply. Most of these dialog boxes, like the Twirl dialog box shown in Figure 13.15, include a graphical representation of what the distortion looks like. In some cases, such as for the Shear filter, the graphical representation may be manipulated to define the distortion.

Figure 13.14. The Displace filter distorts images based on an externally loaded displacement map.

Figure 13.15. The Twirl dialog box includes a Preview pane and also a graphical representation of the distortion that is applied.

Of all the Distort filters, the Wave filter dialog box, shown in Figure 13.16, includes many unique settings for distorting the image such as selecting the Wave Type as Sine, Triangle, or Square, as well as a Randomize button.

Figure 13.16. The Wave dialog box includes many settings for precisely controlling the distortion of an image.

When noise is added to an image, it randomly alters the colors of many of the surrounding pixels, making the image grainy. But it also can be used to blend areas that have been retouched, making them appear more realistic. The Filter

The Add Noise filter opens a dialog box, shown in Figure 13.17, where you can specify the amount of noise to add to the image. The Uniform option randomly adds noise about the selected value, and the Gaussian option adds noise using a bell-shaped average curve. The Monochromatic option causes the noise to be black and white.

The Despeckle filter doesn't open a dialog box, but it removes noise from the image. It also detects edges to maintain the details of the image. The Median filter also removes noise from the image by replacing the brightest and darkest pixels with a median-colored pixel.

Most scratches and dust irregularities are small enough that they may be removed using the Dust & Scratches filter. This filter looks for small abrupt changes that are as small as the designated Radius value and with a given threshold. This filter applies a general blurring of the entire image. Figure 13.18 shows the dialog box for this filter.

Figure 13.17. The Add Noise dialog box determines the amount of noise that you add to an image.

Figure 13.18. The Dust & Scratches dialog box eliminates irregular high-contrast dots and lines from an image.

Adding noise to an image can soften an image by including a grainy feel, but having too much grain can affect image clarity. Some cameras can add film grain to an image and digital cameras add digital noise. Saving images to the JPEG format also can add unwanted noise and can reduce the image to the point that ugly artifacts and distortions appear. Photoshop includes a filter that can help remove noise from an image. It also is found in the Filter

The Reduce Noise dialog box, shown in Figure 13.19, includes a preview pane along with several settings. You can save and recall settings using the Settings dialog box. You also can switch the dialog box between Basic and Advanced displays. The Basic display includes settings for Strength, Preserve Details, Reduce Color Noise, and Sharpen Details. You also have an option to Remove JPEG Artifact:

Figure 13.19. You can use the Reduce Noise dialog box to remove noise and artifacts from images.

If you determine that the luminance noise exists in only a single channel, you can switch to the Advanced display to make a Per Channel pane available. This pane displays the Red, Green, and Blue channels and lets you set the Strength and Preserve Details for only the selected channel.

The Filter

The shapes of the grouped pixels in each of these filters are slightly different, each creating a unique stylized look. For example, the Color Halftone filter changes each pixel group into a circle based on its brightness, the Crystallize filter changes groups of pixels into an irregular polygon shape, the Mosaic filter changes each grouping into a square, and the Pointillize filter groups pixels into solid dots. Figure 13.20 shows examples of several of these filters.

Figure 13.20. The Pixelate filters are used to alter an image by expanding the shape of specific pixel groups.

The process of rendering involves additional computations that alter the image in new and interesting ways. Using the filters in the Render category enables you to create clouds, fibers, and lighting effects like lens flares.

The Render filters include two filters for creating clouds—Clouds and Difference Clouds. The Clouds filter replaces the current image or selection with a random distribution of pixels using the Foreground and Background colors.

Tip

Holding down the Option/Alt key while choosing Filter

The Difference Clouds filter is similar, but instead of replacing the image, it blends the clouds with the image or the selection using a Difference blending mode, which inverts the colors of the image. Figure 13.21 shows an image where the Clouds filter has been applied to the left half, and the Difference Clouds filter has been applied to the right half.

Figure 13.21. The Clouds filter has been applied to the selection on the left of this image, and the Difference Clouds filter has been applied to the right half of the image.

The Render

Lens flares are lighting anomalies that appear when you point a camera at a bright light. The Lens Flare filter opens a dialog box, shown in Figure 13.23, where you can click in the Preview pane to position the lens flare. You also can set the brightness of the lens flare and choose one of four lens types.

Figure 13.22. The Fibers dialog box creates long strands of fiber.

Figure 13.23. The Lens Flare dialog box lets you position the flare by dragging within the Preview pane.

Each of the various lens types creates a different pattern of streaks, rings, and glows. You can see results of each lens type in Figure 13.24.

Figure 13.24. Each of the lens types creates a unique lens flare.

Of the various filters in the Render category, the Lighting Effects filter offers the most functionality. This filter may be applied only to RGB images using the Filter

Warning

The Lighting Effects filter requires a substantial amount of memory, and if your system doesn't have enough memory available, a warning dialog box appears. You can make more memory available using the Edit

When the Lighting Effects filter is applied, the Lighting Effects dialog box, shown in Figure 13.25, is displayed. Using this dialog box, you can add multiple lights to shine upon the image shown in the Preview pane.

Figure 13.25. The Lighting Effects dialog box lets you position multiple lights around the image and change their settings.

To add a light to the image, click the Light icon at the bottom of the Preview pane and drag it into the Preview pane, or hold down the Option/Alt key and drag from an existing light to duplicate the light. All lights appear in the Preview pane as white dots. These lights may be repositioned by dragging the white dots to a new location.

When a light is selected in the Preview pane, an ellipse that represents the light's range is displayed. By dragging on its handles, you can change the light's range. Holding down the Shift key while dragging these handles constrains the ellipse to change only a single dimension.

Lights are deleted by dragging their white dots to the Trash Can icon beneath the Preview pane.

The Light Type field lets you select from three different light types: Directional, Omni, and Spotlight. A Directional light shines light rays from a distant source, and all its rays are parallel much like the Sun. An ellipse represents a Spotlight and controls the Spotlight's angle and direction. A Spotlight decreases in intensity the further from its source it gets. An Omni light, represented by a circle, casts light equally in all directions, much like a light bulb.

Each light is enabled or disabled using the On option. Each light type also has an Intensity value, which may be positive or negative. A negative light value actually pulls light away from the image. Each light also can have a color, which is specified by the color swatch to the right of the Intensity setting. Click the color swatch to open a Color Picker where you can change the light's color.

When the Spotlight type is selected, one end of the ellipse acts as the source and is the brightest point (or the darkest if the Intensity value is negative). The Focus value sets how much of the ellipse is filled with light.

The Properties values determine how the light interacts with the image surface. The Gloss value determines how shiny the surface is and how much the light reflects. The Material setting controls whether the light color (Plastic) or the image color (Metallic) gets reflected. The Exposure setting is a multiplier for the light, and the Ambience setting controls the background lighting in the image. The color swatch to the right of the Properties is for the ambient light color.

The Texture Channel field lets you select a channel and use it to emboss the image by raising the channel relative to the remaining pixels.

With all these controls, it may be difficult to configure an effective lighting setup. Photoshop includes several default Style settings from which you can select. These presets include a variety of settings, and you can save your own presets using the Save button at the top of the dialog box.

STEPS: Applying Lighting Effects

The Sharpen filters are used to enhance the details of blurry images by increasing the contrast of edges. Choose Filter

The Unsharp Mask filter opens a dialog box, shown in Figure 13.28, that lets you adjust the amount of sharpness that is applied. This filter works by increasing the pixel contrast for areas where adjacent pixels have a value that is greater than the specified Threshold. The Radius value determines the size of the area where the pixel values are compared, and the Amount setting controls how much the contrast of adjacent pixels within the Threshold is increased.

Be warned that over sharpening an image adds halos to the image edges. Images that include particularly bright colors may be oversaturated if you set the Amount setting too high. Figure 13.29 shows an image with the Unsharp Mask filter applied to different sections. The left end of the palace image has a large Radius value and a low Threshold causing the contrast to be increased for the entire section. The right end of the image has been sharpened with high Amount and Radius settings and a low Threshold setting, causing the section to be over-saturated. The middle section is unchanged.

Figure 13.28. The Unsharp Mask dialog box lets you control the amount of sharpening applied to an image.

Figure 13.29. The Unsharp Mask filter has been applied to this image using different settings.

The Stylize filters apply a variety of unique effects that give an image a specific style. The filters in this category include the Diffuse, Emboss, Extrude, Find Edges, Glowing Edges, Solarize, Tiles, Trace Contour, and Wind.

The Diffuse filter moves pixels around to make the image appear unfocused. The options include Normal, Darken Only, Lighten Only, and Anisotropic. The Emboss filter colors the entire image gray and raises the image along its edges to form a relief. The Emboss dialog box lets you choose Angle, Height, and Amount values.

The Extrude filter divides the image into squares and then colors each square to look like it is rising from the surface of the image. In the Extrude dialog box, you can select to use blocks or pyramids, set the size of the squares, and set the depth that they rise to.

The Find Edges and Solarize filters are applied without a dialog box. The Find Edges filter identifies all the edges in the image and displays them as dark borders on a white background. The Solarize filter combines the image with the image's negative to produce a darkened image with inverted colors.

The Tiles filter divides the entire image into square tiles and offsets each one slightly. In the Tiles dialog box, you can select the number of tiles and a maximum offset. The Trace Contour filter outlines the edges of the image, based on brightness, and displays them on a white background. The Wind filter spreads the edges of an image in different intensities as if something were dragged over the image when it was wet. Figure 13.30 shows a sampling of the Stylize filters applied to an image.

Figure 13.30. The Stylize filters may be used to create a number of unique effects.

At the bottom of the Filter menu are two miscellaneous filter categories—Video and Other. The Video filters include De-Interlace, which is used to remove interlaced lines from images captured from a video source, and NTSC Colors, which limits the color palette to those used for broadcast television.

The Other category includes the Custom filter. This filter opens a dialog box, shown in Figure 13.31, that includes an array of value fields. Each text field represents the brightness value of the pixels that surround the pixel represented by the center text field. These brightness values can range from −999 to +999. The Scale value is used to divide the sum of all brightness values and the Offset value is added to the brightness values after scaling. By entering custom values into these text fields, you can create your own custom filter. These custom filters may be saved and reloaded as needed. The custom filters are saved with an ACF extension.

Figure 13.31. The Custom dialog box lets you create your own original filters.

The Other category also includes a High Pass filter, which highlights all the sharp color changing edges. The Minimum and Maximum filters look at a grouping of pixels defined by the Radius value and remove the brightest (or darkest) pixel from the group.

The Other category also includes the Offset filter. This filter offsets all the pixels in an image, making the image edges appear within the image interior. This filter often is used to mask the image edges to make an image tileable.

STEPS: Creating a Custom Filter

The Liquify interface may be used to stretch and distort images and image selections as if they were placed on putty. To open the Liquify interface, shown in Figure 13.34, choose Filter

Figure 13.34. The Liquify interface lets you distort images by pushing and pulling pixel areas.

Moving the cursor over the Preview pane where the image is displayed reveals the outline of a brush. The brush options include Size, Density, Pressure, Rate, and Turbulence Jitter. Each of these options is set using the controls listed to the right.

The various liquify tools are displayed in a toolbar to the left of the Preview pane and include the following:

Dragging with any of the Liquify tools in the Preview pane distorts the image. These distortions may be undone using the Reconstruct tool. The Reconstruct tool has several modes including Revert, Rigid, Stiff, Smooth, and Loose. Each of these modes reconstructs the image in a different manner. Pressing the Restore All button returns the image to its original state.

At any time during the modifications, you can use a mask to lock an area from any changes. The Mask Options dialog box includes buttons to replace, add, subtract, intersect, or invert the current mask selection, transparency, or layer mask.

The View Options let you toggle on and off the image, the distortion mesh, the mask, and the backdrop. The backdrop is the faded version of the original image.

STEPS: Using the Liquify Interface

Painting walls in Photoshop is easy enough when the wall is a solid color, but if you're trying to add a patterned texture to the wall, it can be difficult to match the perspective view as you apply the paint. A work-around is to apply a Perspective transformation to the texture before applying the transformation, but you need to match the area exactly or apply it to a different layer that you can clean up later.

Photoshop CS4 has a unique way of handling this complex problem. The Vanishing Point interface, under the Filter menu, has a dialog box that opens with the current image in its preview pane (Alt+Ctrl+V in Windows; Option+

Figure 13.38. The Vanishing Point interface lets you define perspective planes by clicking the plane's four corner points.

After you define a perspective plane, you can use the tools located in the upper-left corner of the Vanishing Point interface to edit the perspective plane, paint, or transform selections. When a tool is selected, its settings appear in the Control panel at the top of the interface. Each of these tools works the same and has the same keyboard shortcuts as the original interface.

STEPS: Using the Vanishing Point Interface

Figure 13.40. With the Vanishing Point interface, the Stamp tool copies image portions while maintaining the perspective view.

The preceding tutorial is a simple example of a single plane vanishing point image, but the Vanishing Point dialog box can deal with multiple grids, enough to recreate a cube. If you hold down the Ctrl/Command key and pull on an edge, a linked grid is created that is positioned at 90 degrees from the original grid. If you click and drag an edge handle with the Alt/Option key held down, you break the 90 degree lock on the linked grids and allow the grids to swing into new positions.

Any new artwork that is pasted into the Vanishing Point dialog box is automatically wrapped around all of the defined grids. Furthermore, if you are using Photoshop CS4 Extended, then you can export the 3D grids and textures to the DXF and 3DS formats for use in a 3D modeling package.