I’m sure you’re asking yourself a couple of questions like what does video safe mean? and why/where would I use this format?
The short answer to the first question is: when graphics are converted to a traditional video signal (called a composite feed) and then sent to a television, there are areas of the image that over-scan (become cropped). You probably remember the old CRT (tube) televisions with the curved surface and the rounded corners. “Video Safe” refers to the areas where both the image and text will be visible and look normal on these old sets. There is an “image safe” area that to which graphic images can extend and a “title safe” area in which text is legible and not cropped.
So you’re probably asking yourself why, in the age of HDTV and computers would creating a presentation in this format still be relevant? The reality is that not all systems are compatible and anytime the computer signal is converted to a video signal, there is the potential for over-scan loss. A good example would be the live capture of slides to video for a webcast. If the system is calibrated to overscan the video signal from the camera to the switcher it may also crop the presentation. Any presentation file being sent to a video for DVD should follow video safe guidelines since playback will most likely occur on any manner of television style. Also, with the weak economy and travel cutbacks, telepresence has lately become quite popular and some of the older units still employ the large CRTs. These units allow you to send graphics which are converted to video signals and again provide he potential for image loss from over-scan.
So here are some guidelines for creating a video safe presentation. If you download the following image (click on the image to get a higher resolution full screen 1024 pixel x 768 pixel version) and stretch it to fill your 4:3 proportion presentation background (in the slide master), you can use this image as a guide and then delete it once you have completed your presentation.
The dotted grey line is the edge of the presentation in PowerPoint. If you are creating a standard on-screen show presentation (which is the default) this will be 7.5 in. x 10 in. in the page set-up. With the ruler turned on, you will notice that 0 in. is the center horizontally and vertically for the slide. The horizontal extends to 5 in. (1/2 of 10) from the center and vertically extends to 3.75 (1/2 of 7.5).
The blue line on the above graphic is the image safe area. On your slide ruler that means that if you had a photo, you could size it to fill from 3 3/8 in. above center vertically to 3 3/8 in. below center vertically and 4.5 in. left of center to 4.5 in. right of center or a total area of 6.75 in. x 9 in.
The green area is where text will not be cut off when it goes to video. On the slide ruler it extends from approximately 3 in. above to 3 in. below and 4 in. left to 4 in. right or a total area of 6 in. x 8 in.
Since standard television resolution is low (usual 720 pixels by 480 pixels and often interlaced which means interleaved every other frame) relative to standard projected resolution (1024 pixels by 768 pixels), it is important to make sure that text is larger than 24 pt. Also, legibility is much improved if the font is a Sans font (like Arial or Helvetica) and not a Serif font (like Times or Schoolbook).
Most importantly and whenever possible, test the file to make sure that it is going to work. Video safe may not be necessary but it may be a necessary precaution.
