In Photoshop, the term animation refers to anything that changes over time. For example, an object can change position in your document and it can also change in size. For example, if the starting position of some text is outside the document’s margins, then it can appear to move across the screen. If an object starts out microscopically small, it can appear to magically zoom itself into view. Along those same lines, an adjustment you apply to a layer can change its opacity over time or even the area to which it’s applied. Layer styles can also change over time. This section shows you how to include all those exciting changes, and more, in your video projects.
The key concept (ha!) to grasp about animations is that everything happens around a keyframe: the moment in an animation when something changes. This could be the direction of an object’s movement, the object’s size, the properties of a filter or image adjustment, or whatever. To create an animation in Photoshop, you create multiple keyframes, and then Photoshop creates the appropriate frames between them (these in-between frames are called tween frames). For example, to create a bouncing ball animation, you’d place the ball on the ground in one keyframe, then you’d move it to the sky in another keyframe, and then you’d place it on the ground again in yet another keyframe; Photoshop then adds all the frames in between to make it look like it’s really bouncing.