A SlideMagic user asked the the other day what to do with a 30 x 10 feet (10 x 3 meter) projector screen that he was supposed to use in a presentation. A 10 x 3 meter screen has a 3:1 aspect ratio and is incredibly wide and "low". Displaying a regular 4:3 slide on it will leave huge black bars to the left and right of the slide.
The first decision you need to make is whether you want to use the entire screen or not. Pro: you can create spectacularly large slides. But there are drawbacks:
- A huge screen might overpower you, the speaker
- It is actually very hard to design slides in this unusual format. Image crops are not natural, and there is almost no avoiding to putting content in boxes from left to right on the slide
- Finally, it is work to do the above
If you decide to go for the full big screen redesign, then you do not need to create a 30 x 10 feet custom slide format in PowerPoint, any 3:1 aspect ratio will do.
No, my presentation app SlideMagic does not support custom screen aspect ratios, that would go against its philosophy.