Point Power: Taking It With You

Point Power is a series of occasional columns that offer tips on how to improve your PowerPoint presentations.

     A lot of us routinely design PowerPoint files to work on other people's computers. There's nothing quite like the experience of putting your all into a dazzling presentation, only to see it succumb to a technological snag.

     PowerPoint 97 was supposed to store typefaces, but some copyright issues put an end to that. As a result, most of us use only the most essential Microsoft fonts. Even Tahoma, Verdana and Arial Black aren't reliable; lots of folks simply don't include them when they install their software. About all you can really count on is Times New Roman and plain old Arial. (Gag.)

     Times New Roman (Microsoft's version of Times) is a terrible font choice for a screenshow presentation, especially at small sizes. Lots of projectors have limited resolutions that make the serifs (those little hangy-down parts on a capital T for instance, or an apostrophe) look fuzzy on the screen. Times was designed for newsprint. It reads well at high resolution, but it's not the best tool for a screenshow. Arial (Helvetica) displays much better on the screen, but it's boring when that's all you've got.

     There are a couple of options. If you have plenty of money (or there's a lot riding on your talk), you can carry your own projector, laptop and cables, and practice like crazy in advance. Or, you can rasterize your slides.

     I'll explain. There are two kinds of digital graphics. Vector art is stored as a series of mathematical instructions that tell a computer how to draw something (like clip art or text) on a screen. It occupies little disk space and can be stretched without any loss of quality. Raster art is made up of individual pixels (called dots when they get to your printer) that are stored and displayed in arrays (like photos). High-quality raster images can occupy a lot of space on a hard drive and can take some time to display on an older computer. If you stretch a raster image, its resolution decreases; if you squeeze it, the resolution increases.

     PowerPoint gives you the option of storing each frame of a screenshow as an individual raster image in your choice of formats and resolutions. (By default, it names each image by its own slide number.) You then create a blank screenshow and insert the images into it, in sequence.

     The procedure is the same on the Mac as it is on the PC. Under the File menu, choose Save As. A window will open that allows you to specify three critical things: the name of a folder where you want your images, where you want the folder placed and the file format you want to use for each image. Choose whatever you want for the first two, but TIF is probably the best choice for the third, and a good resolution is 180 ppi. On the PC, PowerPoint then asks whether you want to save a single frame or every frame in the presentation. You should choose “every frame.” On the Mac, there's an “options” button in the original window that gives you that choice, as well as resolutions and some others. Either way, you have the option to specify “LZW compression.” Choose that; it will decrease your PowerPoint file size drastically.

     Why use the TIF format? Because it's less work when you're inserting the images into your blank frames. If you choose JPG, PNG or BMP, you'll end up stretching each image twice to make it fit the frames of your presentation. (That may be worth the trouble if you think you'll be presenting on an old computer because TIFs are larger files that will slow a computer down.)

     Why specify such a high resolution, since most computers display at 96–120 pixels per inch (ppi)? By giving the host computer more pixels to choose from, you enable it to display your text a little sharper, especially when projected onto a screen.

     It's a good idea to choose a dark background for your blank presentation. Otherwise, if you have a frame that didn't fit perfectly, you'll see distracting light-colored edges in some of your slides when you present them. You'll need to insert new slide transitions if you use them. You'll also need to reinsert any sound bytes or video files you might have included in your original presentation, and include the source files for them with your new presentation file.

     Otherwise, unless there's a power failure, this is a rock-solid way to transport a presentation and be sure it looks the same on a host's computer as it did on yours. Personally, I use it for backups. I carry backup files on a CD and on a compact flash disk. (I never put backup files in any luggage that ever gets out of my sight.)

     Does somebody want you to copy your files onto their computer's desktop? There's a way to do that without leaving your PowerPoint files there. Don't just drag them into your host's trash can where they can be retrieved. Even in EMS, not everybody is inclined to respect your hard work. Instead, while you're still in PowerPoint, open the presentation viewer (it shows all of your slides as little pictures) and erase every frame but the first frame of your presentation. Then go to the slide viewer (it shows an individual slide) and erase the data on the first frame. Finally, save your now-empty PowerPoint file by its original name, close PowerPoint and drag your file to the trash. Your data will be safely irretrievable forever, even on your host's computer.