If you are using PowerPoint on a Mac, you may experience fewer problems if you save your slides in PDF format. By default, saving as PDF will produce A4 landscape documents, and if your slides have a non-white background then they will acquire a white border. Here is a way to avoid this:
- Go to PowerPoint > File > Print
- In the print dialogue box select the "Page Setup" option as highlighted in the image below.
- In the "Page Setup" dialog box select the landscape orientation and then "Options" as highlighted in the image below.
- In the "Page Setup" dialog box select the landscape orientation and then select the "Manage Custom Sizes" from the "Paper Size:" drop down list, as shown in the image below.
- In the "Custom Paper Sizes" dialogue box set the paper width to 20.99cm and length to 27.9cm. Also set all the margins to 0cm and select "OK"
- Click on "OK" button for all the dialogue boxes, till you arrive back at the "Print" dialogue box. At this stage "Preview" the slideshow to ensure there is no white border. If there is, go back to "Page Setup" > "Options" and increase the "Scale" percentage to a suitable value (usually between 110-120%).
- When you are happy, in the "Print" dialog box select the "PDF" button and choose "Save as PDF" as shown below.