Set the frame first
Select a timeline picture clip, place the sequence playhead inside it, and open the inspector. Use spatial conform and transform controls to fit the source to the canvas, then refine scale, rotation, and position. Inspect the edges for unintended empty areas. Opacity controls how much of that layer is visible.
If you duplicate an edit for a different aspect ratio, review every shot in motion. A face that fits at the first frame may leave the canvas later. Use keyframes for supported changing values and format copies for separate delivery canvases.
Add a composition operation
Open Clip → Compositing, or use the composition inspector. Add Operation offers Crop, Rectangle mask, Ellipse mask, Draw mask, Gradient mask, and Chroma key. Each solves a different problem: crop removes edges, a mask isolates an area, and a keyer removes a chosen background color.
Blend modes change how a layer combines with what is underneath. Begin with Normal. Multiply, Screen, and other choices can produce striking results, but inspect shadows, highlights, and transparency after changing them.
Inspect the matte
Use matte preview to see the transparency result clearly. Check the whole shot, especially fine edges and movement. Mask combinations can add, subtract, or intersect regions; the order and selected effect determine the result.
Crop-to-fill reframes the remaining window, while a trim-style crop leaves removed edges transparent. Keep a nonempty crop window. Transparent edges in the preview require a compatible alpha output when exporting; otherwise the delivery may flatten them against its background.
Add color and effects with restraint
Basic picture controls include exposure, contrast, saturation, temperature, tint, highlights, shadows, vignette, grain, glow, blur, and monochrome. Correct exposure and color balance before styling. Use the ordered correction stack for primary corrections, curves, and LUTs, and compare neighboring shots.
Copy Clip Settings and Paste Clip Settings transfer chosen attributes; inspect the paste choices instead of assuming every value should travel. If a clip has animation, check whether inspector edits affect the value at the playhead or the whole curve.
Verify the result
Play across the operation at normal viewing size. Watch for edge flicker, excessive blur, unintended changes to a neighboring layer, and text becoming unreadable. Export a short representative interval before committing a long delivery.
This guide covers controls present in the Mac interface. The iOS inspector has its own arrangement, described in color, framing, and layers on iOS. Specialist tracking and repair workflows need their own validation; a saved tracking record is not proof that a mask follows every frame correctly.