Masking will determine which areas of your cinemagraph are in motion; use the brush tool to reveal motion from your video and the eraser tool to remove it. Cinemagraphs can be easily created when there is a clear separation between the motion and still components.
However, sometimes you’ll record a video with motion overlapping in the foreground and background, making certain areas more difficult to mask. In these scenarios, you can adjust the size, hardness, and opacity of the brush and eraser tools to apply a precise mask.
Size | You can adjust the size of your brush and eraser by dragging the slider left or right. Adjusting the size of will help you cover large areas quickly or go into small details. Zoom in and out of your cinemagraph by pinching in and out on your trackpad or using the keyboard shortcuts ⌘+ and ⌘-.
Hardness | You can adjust how hard or soft the edge of your brush and eraser are by dragging the slider left or right. Use a softer brush if your subject doesn't have clearly defined edges.
Opacity | You can adjust how transparent your brush and eraser are by dragging the slider left or right. Decreasing the brush opacity will allow you to blend the still image with the motion in your cinemagraph. This process is often necessary when you cannot see a clear separation between moving subjects in your video. Use a transparent brush to create double exposure cinemagraphs.
Note: In order to successfully blend the still and motion components of your cinemagraph, the overlapping motion must be subtle. This process may take some experimentation before creating the perfect mask for your cinemagraph.