Just as the term motion properties is used to describe a collection of tools that do a lot more than move things, so the term filters applies to a lot more than just tools for tinting or texturing an image. Final Cut Express comes with more than 50 video filters with a wide variety of uses. In addition to a suite of image-control filters for color correction and tinting, Final Cut Express provides filters you can use to blur, twirl, emboss, ripple, flip, mask, and key. For a list of filters, refer to Chapter 29 in Apple’s Final Cut Express Help PDF.
But wait—there’s more. Final Cut Express can also make use of the QuickTime effects that are installed with QuickTime and some FXBuilder-based filters written for Final Cut Pro.
You’ll find filters on the Browser’s Effects tab or the Effects menu. After installation, QuickTime effects and third-party filters are stored in separate folders within the main Video Filters folders.
For information on working with audio filters, see Chapter 12, “Audio Tools and Techniques.”
Do one of the following:
Drag the filter from the Browser’s Effects tab and drop it on the clip in the Timeline (Figure 16.1).
Select the clip in the Timeline, choose Effects > Video (or Audio) Filters, and make your filter selection from the submenu.
Position the playhead over a frame in the selected clip to see a preview of the effect in the Canvas (Figure 16.2).
Tips
Many filters’ default settings have no visible effect on a clip. You must adjust settings before you can detect a difference.
Final Cut Express renders a clip’s filters in the order they appear on the Filters tab. You can drag a filter up or down in the list to rearrange the filter order. Rendering order affects your final results.
To apply a filter to a range of clips or part of a clip:
From the Tool palette, choose the Range Selection tool (Figure 16.3).
In the Timeline, drag to select whole or partial clips.
Choose Effects > Video (or Audio) Filters and select a filter from the submenus (Figure 16.4).
If you selected multiple clips, Final Cut Express adds a separate copy of the filter to each clip.
Position the playhead over a frame in the selected clip range to see a preview of the effect in the Canvas.
To use Auto Select to apply a filter to multiple clips:
In the Timeline, set In and Out points at the boundaries of the section where you want to apply the filter.
Make sure the Auto Select control is enabled on all tracks where you want the filter to be applied; disable any tracks containing clips that you want to exclude from filtering (Figure 16.5).
Figure 16.5. Auto-selected clips appear highlighted in the Timeline; In and Out points mark the boundaries of the selection. Disabling the Auto Select control on V1 will exclude V1 clips from the batch filter application. Make sure the Auto Select control is enabled on all tracks where you want the filter to be applied.
Choose Effects > Video (or Audio) Filters and select a filter from the submenu.
If you selected multiple clips, Final Cut Express adds a separate copy of the filter to each clip between the In and Out points on tracks where Auto Select is enabled.
Position the playhead over a frame in the selected clip range to see a preview of the effect in the Canvas.
In the Timeline, double-click a clip to which you’ve added a filter to open it in the Viewer.
In the Viewer, click the Filters tab to access the filter’s controls.
Configure the filter’s settings (Figure 16.6). The items you can change vary according to the type of filter.
To see your changes, use the arrow keys to move through the clip frame by frame, or try a low-quality real-time preview. For the highest-quality playback, render the clip; then you can play it with a video filter applied.
To disable a filter:
In the Timeline, double-click a clip to which you’ve added a filter; then select the clip’s Filters tab.
Uncheck the box next to the filter’s name on the Viewer’s Filters tab.
The filter is disabled but still applied to the clip. To toggle it on, recheck the box.
Tip
If you need more space to adjust sliders (or to read the full name of a filter control), expand the columns containing the effect controls on the Filters, Controls, and Motion tabs. Drag the column header separators to adjust column width (Figure 16.7) or drag the lower-right corner of the Viewer to expand it horizontally.
To remove a filter from a clip:
Do one of the following:
Select the filter on the Filters tab and press Delete.
Control-click the filter and choose Cut from the shortcut menu.
Select the filter and choose Edit > Clear.
Like editing, color correction is an invisible art. It’s an essential part of post-production that can have a significant impact on a show, but it’s not a high-profile part of the process. Final Cut Express introduces an improved set of image-quality measurement and color correction tools that make it feasible to complete a broadcast-quality finished product without leaving the Desktop.
At the most basic level, you can use these tools to ensure that the video levels in your finished program don’t exceed broadcast-legal limits. If the video in your program already looks good, careful color correction can make it look even better—if you have exposure problems or intercut shots that don’t match, color correction can salvage your show. You can also use color correction tools to completely transform the look of your footage or to create an illusion—one example is “day for night,” an old movie trick where scenes shot during the day are printed very dark to simulate night lighting.
This section provides a brief overview of the tools and the basics of working with the Color Correction filter interface, but it does not delve into the complexities of color correction (there are entire books written on the subject). You should supplement your reading with Chapter 31 of Apple’s Final Cut Express Help PDF, a 20-page introduction to the principles of color correction and the protocols governing the operation of Final Cut Express’s color correction tools. Be sure to use the full-color PDF version of the manual; any demonstration of color correction technique is severely handicapped when it’s presented in grayscale. The PDF version of the manual is available from FCE’s Help menu.
You’ll find five filters in FCE’s Color Correction filter folder (Figure 16.8). Some of the filters are general-purpose color correction tools; others have special applications. It’s common to use more than one filter type on a single color-corrected clip.
Figure 16.8. These five filters make up FCE’s color correction suite. Some, like the Color Corrector, are general-purpose color correction tools; others, like the Desaturate Highlights filter, have special uses.
Broadcast Safe: This filter is designed to clamp (filter out) any illegal luma and chroma levels in your clip. See “Using the Broadcast Safe filter” later in this chapter.
Color Corrector: This filter is for general-purpose color correction and offers both numerical controls and graphical onscreen controls. For more information, see “Anatomy of the Color Corrector tab” later in this chapter.
Desaturate Highlights/Desaturate Lows: These two filters (actually the same filter with two different default settings) are designed to solve a common color correction problem: altering or increasing the intensity of a color in your image without tinting the highlights or black areas of the image. These filters desaturate (reduce the chroma levels) in those areas of the image, keeping your whites and blacks pure.
RGB Balance: This simple RGB color balance filter has separate highlight, midtone, and blacks controls for reds, greens, and blues.
The Broadcast Safe filter is a quick fix you can apply to any NTSC or PAL video in your program. The filter offers a menu of presets (Figure 16.9) designed to clamp any illegal luma or chroma levels in your clip to within legal limits. The default setting should work well for most clips, but if you want to tweak the settings yourself, you can choose the Custom setting, which enables the individual luma and chroma level controls. The filter displays NTSC or PAL broadcast-safe presets based on your sequence settings.
Figure 16.9. The Broadcast Safe filter offers a menu of presets designed to clamp illegal luma or chroma levels in your clip to broadcast-legal limits. The filter’s default settings work fine in most cases.
Tips
You can apply a single Broadcast Safe filter to your entire sequence by nesting the sequence inside a parent sequence before you apply the filter. To learn more about the care and feeding of nested sequences, see “Working with Multiple Sequences” in Chapter 4.
Once you’ve applied the Broadcast Safe filter, your image may appear a little too dark and desaturated on your computer monitor; remember to reserve final judgment until you’ve scrutinized the picture on an external broadcast monitor.
The Color Corrector filter—one of the five filters available in FCE’s Color Correction filter folder—features graphical onscreen controls in addition to the standard numeric controls found on the Filters tab of the Viewer. The visual controls appear on their own Viewer tab after you apply the Color Corrector filter (Figure 16.10).
Tip
Position the pointer over a filter control in the interface to display a tooltip with the name of the control and its keyboard shortcut equivalent.
The top section of the tab contains clip controls for keyframing the color correction filter and for copying the filter’s settings to other clips in your sequence.
Color Corrector Viewer tabs: The filter’s visual controls appear on their own Viewer tab. If you have multiple copies of the Color Corrector filter applied to the clip, a separate numbered tab appears for each copy.
Numeric button: Click this button to switch to the filter’s numeric controls on the Filters tab.
Enable Filter check box: Check to enable this filter. Uncheck to disable the filter.
Copy Filter controls: The Copy Filter feature (Figure 16.11) is one of the secret weapons of the Color Corrector filter. Once you have color corrected a representative shot in your sequence to your satisfaction, you can use the Copy Filter controls to copy your filter’s settings to other clips in your sequence with a single mouse click.
Figure 16.11. Use the Copy Filter controls to copy your filter settings to other clips in your sequence with a single mouse click.
Copy from 2nd Clip Back: Copies settings from the Color Corrector filter that is applied two clips upstream from the currently selected clip and pastes the settings into this copy of the Color Corrector filter, replacing any previously applied settings. If the source clip has no color correction filter, this control is dimmed.
Copy from 1st Clip Back: Copies settings from the Color Corrector filter that is applied to the first clip upstream from the currently selected clip and pastes the settings into this copy of the Color Corrector filter, replacing any previously applied settings. If the source clip has no color correction filter, this control is dimmed.
Copy to 1st Clip Forward: Copies the settings of this Color Corrector filter into the next clip downstream in your sequence. If no Color Corrector filter is present on the destination clip, FCE applies one automatically.
Copy to 2nd Clip Forward: Copies the settings of this Color Corrector filter into the clip located two clips downstream in your sequence. If no Color Corrector filter is present on the destination clip, FCE applies one automatically.
Drag Filter control: Drag this button to another Timeline clip to copy the current Color Corrector filter and its settings into that clip.
The tab’s center section contains the filter’s Color Balance controls and Level and Saturation controls, your everyday color balance tools.
Color Balance control: Use the Balance control like a virtual trackball control. Click the dot at the center of the control and drag it across the circular face of the control to adjust the color balance of your clip. The center of the circle represents pure white; drag farther from the center to increase the saturation of your color shift.
Hold down the Shift key while dragging to constrain the angle of the adjustment—a useful technique for adjusting the intensity of a color without shifting its hue.
Hold down the Command key while dragging to gear up the control, increasing the magnitude of the color balance adjustments in response to your mouse movements. (This is the opposite of the Command-drag gear-down modifier implemented elsewhere in FCE, which enables precision adjustments.)
Select Auto-balance Color eyedropper: Click the eyedropper icon; then click a color in your image that you want to match to the color you selected with the Hue Match controls. For more information, see “Hue Match controls” later in this section.
Balance Reset button: Click to reset the Balance control to its default settings. Shift-click the button to reset the Levels and Sat(uration) sliders to their default values as well.
Hue control: Click the outer edge of the Hue control’s circular face and rotate the dial to make an overall adjustment to the clip’s hue.
Hue Reset button: Click to reset the Hue control to its default settings. Shift-click the button to reset the Levels and Sat(uration) sliders to their default values as well.
Levels sliders: Use these sliders to make overall adjustments to the luminance levels in your clip. Click the tiny arrow at either end of a slider to nudge the value by a single increment.
Whites slider: Use the slider to adjust the clip’s maximum white level.
Mids slider: Use the slider to adjust just the midtones in the clip, leaving any black or white areas untouched.
Blacks slider: Use the slider to adjust the clip’s minimum black level.
Sat(uration) slider: Move this slider to make overall adjustments to the color saturation levels in your clip. Click the tiny arrow at either end of the slider to nudge the value by single increments. Moving the slider all the way to the left removes all color from the clip, leaving a grayscale image. Moving the slider all the way to the right will almost certainly push your color values into distortion, so use caution and check your work on your broadcast video monitor.
Auto White Level button: Click to find the maximum white level in the current frame and automatically adjust the Whites slider to set the maximum white level.
Auto Contrast button: Click to set Auto black and Auto white levels in a single operation.
Auto Black Level button: Click to find the maximum black level in the current frame and automatically adjust the Blacks slider to set the maximum black level.
Hue Match controls: Hue Match controls extend the function of FCE’s auto-white balance controls, allowing you to adjust any color in your image to match the color you’ve selected as the match color. For more information, see “Hue Matching Controls” in Chapter 31 of Apple’s Final Cut Express Help PDF.
Select Match Color: Use the eyedropper to select the color hue you want to match.
Match Color: This swatch displays the color you’ve selected as the auto-balance target color.
Reset Match Color: Click to set the match color to white, the default setting.
Tip
To use Hue Match as an auto-white balance tool, click the Reset Match Color button to set the tool to white, its default setting. Next, use the Select Auto-balance Color eyedropper icon to click a highlight in your image that you want to match to white. The Hue Match control analyzes the hue value of the selected pixel and then automatically adjusts the overall color balance of the image; for example, selecting a light-green highlight will result in an overall color shift toward magenta to correct the green highlight to neutral white.
Compositing can be any process that combines two or more image layers to create an effect. A compositing process can also include filters and motion that have been applied to modify individual layers or to modify the composited image.
A Composite mode is an algorithm, a mathematical formula that controls the way the colors in a clip combine with the clip colors in underlying video layers.
All compositing happens from the top down; the highest-numbered track’s image sits on the front plane and obscures the image on a track beneath it, unless the foreground image is made transparent. Each clip’s opacity setting influences the final effect of the Composite mode.
For a complete list of Final Cut Express’s Composite modes, refer to Chapter 27 of Apple’s Final Cut Express Help PDF.
To set the Composite mode for a clip:
Select the clip in the Timeline; then do one of the following:
Choose Modify > Composite Mode; then select a Composite mode from the submenu (Figure 16.12).
Control-click the clip in the Timeline and then select a Composite mode from the submenu.
An RGB image is composed of three 8-bit grayscale images—the red, green, and blue color channels—that express color information as a gray scale: 256 brightness values (ranging from 0 for black to 255 for white), plus an alpha channel. An alpha channel is a fourth 8-bit channel that can be assigned to an RGB image to track which areas of the image are transparent.
Figures 16.13, 16.14, and 16.15 illustrate how an alpha channel can be manipulated to mask selected areas in an image.
Figure 16.14. The image’s alpha channel. With the alpha channel set to Straight, the white area will be interpreted as transparent.
Figure 16.15. The graphics frame superimposed over video. With the frame’s alpha channel set to Straight, the white areas in the alpha channel shown in Figure 16.14 are made transparent here, allowing the video background to show through.
Alpha channels are useful critters with a variety of applications in digital imaging. Final Cut Express video clips automatically have alpha channels assigned to them; it’s the alpha channel that’s being manipulated when you adjust the opacity of a clip or apply a key or matte filter.
When you import an image that has an alpha channel, Final Cut Express interprets the clip’s alpha channel and sets it to Straight, Black, or White (corresponding to the background setting for the clip at the time the clip was created).
When you place a clip in a sequence, Final Cut Express automatically makes the alpha channel area transparent. You can override the automatic setting by modifying the alpha channel type.
You can reverse an alpha channel if you want to invert the transparency of an image, or you can choose to ignore the clip’s alpha channel altogether.
To view or modify a clip’s alpha channel type:
Select the clip.
Choose Modify > Alpha Type and select a different alpha channel type from the submenu (Figure 16.16).
Tip
DV clips do not retain their alpha channel information if you export them in a DV format. If you want to save a clip’s alpha channel when you export, use the Animation codec, set to Millions of Colors+. If you’re exporting FCE elements for processing in a digital effects creation program such as Adobe After Effects, this is the way to go. Use the Animation codec again when you export from After Effects.
Mattes are filters that you shape to define which areas of opaque video clips are to be made transparent during compositing. For example, you could use a circular matte to isolate a clock face from its background, or you could create a matte in the shape of a keyhole to simulate peeking through a keyhole in a door.
Final Cut Express offers many types of matte filters (Figure 16.17). “Garbage mattes” are used to quickly rough out large areas of the frame. A key is a type of matte that uses a clip’s color or luminance information to determine which opaque areas will be made transparent (bluescreen effects are created with color key mattes set to make blue areas transparent). You can combine layers of different types of mattes to create very complex composite shapes.
Figure 16.17. Final Cut Express offers a toolbox full of special-purpose matte and key filters. When you create multilayer compositions, use these filters to mask out portions of the frame.
To apply a matte:
Do one of the following:
Drag the Key or Matte filter from the Browser’s Effects tab and drop it on the clip in the Timeline.
Select the clip in the Timeline and choose Effects > Video Filters; then select a filter from the Key or Matte submenu.
Position the playhead over a frame in the selected clip to see a preview of the effect in the Canvas.
A travel matte allows one video clip to play through another. The alpha information in a third clip is used as a matte that defines the transparent and opaque areas of the composited image.
When you create a travel matte effect, there are usually three video tracks involved; this is sometimes called a “matte sandwich.” The background clip is placed on V1, or the lowest video track available. The matte clip, preferably a high-contrast, grayscale motion clip or still image, goes on the video track just above the background clip, on V2; and the foreground clip sits on V3, or the video track above the matte clip. A Composite mode specifically for creating travel mattes, called Travel Matte - Luma, is applied to the foreground clip. If the matte clip is placed on video track V1 without a background clip, then the background is automatically black.
To create a travel matte:
In the Timeline, drag your background clip (Figure 16.18) to V1.
Drag the clip selected to be the matte clip (Figure 16.19) to V2.
Drag your foreground clip (Figure 16.20) to V3.
To establish the travel matte, select the foreground clip on V3 (Figure 16.21) and choose Modify > Composite Mode > Travel Matte – Luma.
Figure 16.21. To composite the travel matte, select the foreground clip on V3 and choose Modify > Composite Mode > Travel Matte–Luma. The foreground clip on V3 is now composited with the matte clip on V2.
The completed travel matte effect (Figure 16.22) uses the matte clip’s luminance (or grayscale) levels as the mask. The matte clip’s black area creates the shape of the foreground clip’s transparent areas, revealing the background clip video. The matte clip’s white area creates the shape of the foreground clip’s opaque areas—that’s where you see the foreground clip’s video.
Tips
After you composite your travel matte, you can refine the effect by adjusting the matte clip’s brightness and contrast.
You can apply animated filters and effects, as well as any other standard clip motion, to the travel matte on V2 for some very interesting looks.
Play with Edge Feather and Edge Thin to soften the halo effect you might find around your matted objects when working with color keys.
DV video is not the best video format for creating effects that require critical color key mattes, such as bluescreen or greenscreen effects. DV compression throws out too much color information to give you the best control over edges.