Preparing a movie for import when final output is NTSC interlaced video

You can edit and prepare video footage in other applications, such as Adobe Premiere, before importing it into After Effects. If you want to render the footage from After Effects as NTSC interlaced video, do not field-render or create interlaced frames when you render the movie from the other application. It's acceptable to render interlaced video for temporary files, but 60 progressive gives better quality. Make sure that you keep track of the original field order so you can correctly render it in After Effects. (See Field rendering and Testing the field-rendering order.)

As long as the footage is on a computer, it should remain noninterlaced. Keeping the footage in noninterlaced format preserves more image quality and saves you the extra step of separating fields in After Effects. Once it's ready to go to your nonlinear editor, such as Adobe Premiere, it should be interlaced.

When you render the movie from the other application, render it at 60 fps of frame-rendered (noninterlaced) video. After you integrate it into a composition, After Effects can render it to high-quality field-rendered (interlaced) frames at 30 fps for videotape.