An exposure sheet (also referred to as camera instruction sheet, dope sheet or X-sheet) is a traditional animation tool that allows an animator to organize their thinking and give instructions to the camera operator on how the animation is to be shot.
Every eighth line down is marked thicker than the rest and shows half a foot of film.
One second of animation would take three of these sections (hence every line represents 1/24th of a second).
Sound breakdown was often done on separate sheets called bar sheets made by the editor, and given to the animator who would transpose them to his dope sheet.
The typical dope sheet is divided into sections which are separated by many vertical and horizontal lines, the horizontal lines represent one frame of film while the vertical ones separate the sections, for example:[1]