1. Enter the design page, open the presentation, and click the design option in the menu bar.

2. Click ppt slide size, and select the slide size option in the property bar.

3. Set the size, and select the appropriate size or custom size from the drop-down options. Ppt slide, also known as positive film, is a negative or film. Common specifications are 135 and 120. Usually in color, but there are also black and white positive films for special purposes. It can also be used to print or enlarge photos.