Size

One key component of the size of an overhead projector is the lumen output from the bulb. A higher lumen projector is visible in a brightly lit room. A lower lumen projector requires dimming the room lighting to be clearly visible. The size of the stage is also another element of the size of an overhead. The stage of a projector should be adequate to hold a standard size sheet of paper, which is also the standard size of an overhead transparency.