In the past two lessons, I showed you how to piece together a basic iMovie project as well as how to create an iMovie trailer. Helpful as those lessons were, much of iMovie 10's editing power is hidden. Now it's time to unearth those features. We'll start with making more-exacting edits.

Read next: How to change speed in iMovie for iPad

The clip trimmer

As you've learned, within the timeline you can drag the bottom corners of a clip's edge to shorten or lengthen the clip (assuming, in the latter case, that you're not already working with the entire original clip). This is a perfectly reasonable way to trim clips, but in a way you're working in the dark: You can't see what precedes or follows the edges of the clip. This is where the clip trimmer comes in.

Double-click the clip, and the clip trimmer opens above the timeline. The portion of the clip that's currently active is bright and shiny. Any material that occurs before or after the active clip bears a gray sheen. To move either the beginning or ending edit point, click and drag the white line that denotes the clip's edge. Drag the line toward the center of the clip, and the clip shortens. Drag it away from the center, and the clip lengthens. In the viewer pane above, you'll see the beginning of the active portion of the clip.

You can also adjust the clip's beginning and end points by clicking somewhere other than on those lines and drag the clip to the left or right. When you do this, you're choosing a different chunk of the clip--asking it to begin and end three seconds earlier, for example. Its length doesn't change.

The precision editor

While the clip trimmer deals with the beginning and end of a clip you place in the timeline, the precision editor is for acting on the point where two clips meet. With it you can choose to move a transition, make a transition longer or shorter, choose a new edit point, or extend an audio track.

In a timeline that holds two or more clips, double-click the edge of one of the clips to open the precision editor. You'll know that you're in the precision editor when you see gray dots with black centers sitting above the beginning and end of the timeline's clips.

Click one of these dots, and the clips move. The clip before the dot moves above the later clips and shows in its entirety--the active part of the clip is bright, and the inactive portion is dull. Drag the dot to change where one clip moves to the other. For example, drag the dot to the left, and the second clip will play earlier and be longer (and the first clip will be shorter). Drag the dot to the right, and you extend the first clip and shorten the second.

You can independently shorten or lengthen a clip's audio track. Before you can do that, you must reveal your clips' waveforms if they're not currently showing. Click the Adjust Thumbnail Appearance icon (the one that looks like a film frame) in the top-right corner of the timeline, and enable the Show Waveforms option.

In the blue audio track that appears below the video thumbnail, click the line that denotes the end of the active portion of the clip, and drag. If you drag it to the right--beyond the bounds of the active portion of the video clip--the audio will continue playing into the next clip. You'd do this for a cutaway shot in which a soundtrack or narration continues to play but you're showing another piece of video or a still.

Finally, you can change the length of a transition. If you've added a transition between clips, and you invoke the precision editor, you'll see a gray bubble with dots on either end and arrows inside. This represents the length of the transition. To extend the transition, just drag one of the dots away from the center. As you do, you'll see a time readout that indicates how long the transition now is. Drag a dot toward the center, and it gets shorter. You can also move the transition earlier or later by clicking in the middle of the bubble and dragging it to the left or right.

Making adjustments

The past couple of iMovie versions offered windows and tabs for mucking about with color, cropping, audio, and effects. With iMovie 10, Apple has gathered together those features and placed them in a single Adjust toolbar, which you access by clicking the Adjust button at the top of the iMovie window. Here's what it contains.

Color balance: The color balance control lets you easily change the tone of your clip, via Auto, Match Color, White Balance, and Skin Tone Balance options. The Auto option prompts iMovie to analyze the current frame and change the color cast of the clip based on its calculations of what looks best.

With Match Color, the viewer presents a split view--one portion displays the current frame, and the other shows a frame with a look that you'd like to mimic in the current frame. For example, if you've shot footage on two different days under somewhat different conditions, and you'd like the clips to look similar, you'd match one clip to the other. You'd navigate to the second frame by skimming over a clip and clicking your ideal frame.

The White Balance option lets you automatically choose a white balance based on a neutral color--white or gray, for example--in the frame. When you choose this option, the eyedropper tool appears. Click a neutral color within the frame to change the balance.

The Skin Tone Balance option works similarly. Click the eyedropper on the skin of someone in the frame; the color shifts to balance against that tone.

Color correction: You adjust color correction through the use of three sliders. The first is for tweaking brightness and contrast. It holds five controls, which are, from left to right, Adjust Shadows, Adjust Contrast, Adjust Brightness, a second instance of Adjust Contrast, and Adjust Highlights. The presentation of these tools isn't entirely intuitive, but if you've used the Adjust pane within iPhoto, you'll catch on pretty quickly.

The second and third sliders are more straightforward. One is for adjusting the clip's saturation, and the other is for changing the clip's color temperature, with colder colors on the left and warmer tones on the right.

Crop: Just as you could with older versions of iMovie, in this version of the program you can adjust a clip's cropping and rotation. And the tool works just the way it always has.

For cropping you have three styles--Fit, Crop, and Ken Burns. To force the clip to appear in its original aspect ratio, choose Fit. If the original clip or still image doesn't fit the frame exactly--it shows black bars on the sides, for example--it won't fill the frame. If you choose Crop instead, you can resize the clip to fit in the frame. You could, for example, crop to remove someone on the left side of the frame. When you do so, everything else in the frame will increase in size to make up for the crop.

"Ken Burns" is the name for iMovie's pan-and-scan effect in which the "camera" moves across the frame and zooms in or out. It's named in honor of the documentary director who used this technique extensively to give motion to still images taken during the Civil War and in the early days of jazz and baseball.

To use the effect you first adjust the solid rectangle marked Start. This rectangle determines what the frame looks like when the clip begins. Then you click the dotted rectangle marked End, and size it to encompass the area that you want to fill the frame at the end of the clip. To impose the effect, click the checkmark icon to the right. When you play the clip, it will begin at the Start point and then, over time, move to the size of the End frame.

It's important to note that the Ken Burns effect works across an entire clip. You can't impose it on just a portion of a clip. If you'd like to do that, select the clip in the timeline, Control- or right-click it, and choose Split Clip at the point where you want Ken to finish his business. Now you can apply the effect to just that portion of your movie.

To the right of the crop style buttons are two rotate buttons for turning the frame 90 degrees counterclockwise and clockwise, respectively.

Stabilization: Two controls appear when you select the Stabilization control--Stabilize Shaky Video and Reduce Rolling Shutter Distortion. And they do what, exactly?

Suppose you're filming your surroundings with your iPhone while traveling through a nature preserve in a car with poor shocks on a road full of deep potholes. To help reduce the chance that your audience will suffer motion sickness from your movie, it would be nice if you could remove some of the bouncing from your footage. With the Stabilize Shaky Video option, you can. Enable the option, and iMovie will analyze the selected clip, looking for shaky video. When it completes its analysis, it crops the video to cut out the edges, and at the same time it attempts to take the shake out of the remaining frame. The more stabilization you apply (from 0 to 100 percent), the greater the crop will likely be.

Rolling shutter is a distortion effect that you can get when certain kinds of camera sensors are tasked with capturing a lot of movement or subjected to some varieties of pulsing or flickering light. iMovie will attempt to remove this effect when you enable the Fix Rolling Shutter option. You can choose how much of the option to apply--Low, Medium, High, or Extra High. If you notice the problem, start with Low and work your way up if the currently selected setting doesn't improve your movie. (Undo the last setting by clicking the Undo arrow icon to the right, and then try the next highest setting.)

Volume: Here you find controls for adjusting the sound of the selected clips. The first control on the left is Auto, which "normalizes" the audio so that the loudest sounds in the audio track are increased to the point just below distortion and quieter audio is brought up proportionally.

Next is a Mute button for entirely muting selected clips' audio. You can also use a volume slider to increase or decrease the audio of the selected clips.

And then there's the Lower Volume Of Other Clips slider. In the audio business this technique is known as "ducking." What you're asking iMovie to do is to ensure that the audio within your clips is louder than any other audio track that's playing at the same time--a background music track, for example.

While not obvious, there are a couple of ways you can manipulate audio directly within the waveform view. If you want to change the clip's overall volume, just click and drag up or down on the thin gray audio-adjustment line that appears in the middle of the waveform.

The waveform also has fade controls in the form of small dots that appear on both ends of this line. Drag the left dot to the right to create a fade-in effect. Drag the dot on the right to the left, and the audio fades out.

You can adjust audio within a single clip, as well. Hold the Option key and click points onto the audio-adjustment line. Drag these points up or down to increase or decrease that portion of the audio respectively.

Noise reduction and equalizer: Although iMovie is anything but a full-featured audio-editing application, you can attempt to enhance your audio in a couple of ways. Click this adjustment, and you spy two options. The first is for reducing background noise; you use the slider to adjust how much noise to let through.

Note that this is a pretty broad effect. If someone is running a vacuum cleaner in the background, for instance, you won't be able to get rid of that sound. And even removing a less obnoxious hum may cause some of the sound you want to keep to be affected. In short, don't expect miracles.

This adjustment also offers equalizer presets that emphasize or deemphasize certain audio frequencies--to bring up the bass or treble, for example. The presets include Flat, Voice Enhance, Music Enhance, Loudness, Hum Reduction, Bass Boost, Bass Reduce, Treble Boost, and Treble Reduce.

Video and audio effects: If you've been hunting around for iMovie's effects, this is where they're hiding. Select your clips in the timeline, choose this adjustment, and you find two pop-up menus. The first, Video Effects, offers 19 effects such as Flipped, Film Grain, Vignette, Black & White, and Sepia. Hover your pointer over an effect to see it applied to a sample of your video in the viewer. Click an effect to apply it.

The nearby Audio Effect menu allows you to add any of 19 sound effects to your clip's audio track. The reverb effects (small room, medium room, large room, and cathedral) could be useful. The others are mostly for goofing around.

Info: While the last adjustment in this area may not sound like much, it does provide one control. Select a clip, and you'll see its duration in the field of the same name. Enter a different duration, and the clip expands (up to the length of the source clip) or contracts. When it contracts, the video doesn't speed up--rather, the clip ends sooner than it did prior to your making the adjustment.

Speed effects

Speaking of adjusting the speed of your clips, you have ways to do that, too. iMovie not only lets you slow down and speed up your clips, but also includes an Instant Replay effect that works great with the sports videos you might shoot (or those precious pie-in-the-face moments).

To adjust a clip's speed, first select it in the timeline. Under the Modify menu you'll find Slow Motion, Fast Forward, Instant Replay, Rewind, and Reset Speed commands.

Slow Motion and Fast Forward are for slowing down and speeding up the action (and audio) respectively. The first gives you options for slowing down the video by 50, 25, or 10 percent. The Fast Forward submenu lists 2x, 4x, 8x, and 20x adjustments. When you apply one of these effects, a chrome dot appears in the top-right corner of the clip, indicating that the speed has been adjusted. You can then play with that adjustment by dragging the dot: Drag to the right, and the clip slows down. Drag it to the left, and the clip plays faster. A rabbit or turtle icon imposed on the clip indicates whether the clip is currently playing faster or slower than the original.

The Instant Replay effect takes the selected clip and replays it, imposing an "Instant Replay" title over the top-right corner of the clip. This command's submenu offers options of 100, 50, 25, and 10 percent; the numbers refer to the speed of the resulting replay. Choose 100 percent, for example, and the clip will play at the same speed as the original. A 10 percent setting provides you with a replay ten times as long (and ten times as slow) as the original.

The Rewind effect appends a reversed copy of the clip to the end of the clip and plays it at 1x, 2x, or 4x speed. It then repeats the original clip. Imagine playing some video on your camcorder, pressing Rewind, watching the video and audio scrub back, and then pressing Play to start playing it normally again, and you understand the nature of the effect.

Enhancing the end

It's time your movie (and this lesson) came to an end. Let's finish off the first in style with one of a few other effects.

Select your final clip, and return to the Modify menu. From there you can choose a couple of different ways to finish off your movie with a touch of flair. Selecting Fade To and then Black and White, Sepia, or Dream is a nice way to wrap up a retrospective movie--something for your parents on their 30th anniversary, or for your daughter when she's about to be married. The 'Flash and Hold Frame' effect is also nice. It causes the clip to fade to white, creates a still of the last frame, and then zooms out from that still. It's not an appropriate effect for everything, but in the right settings it's lovely.

Next week: Wrapping up iMovie 10