The video window on YouTube and most other places on the Web is very small. A presentation that looks great on your laptop screen or through a projector will probably not look very good in that tiny window and it may not even be readable at all, especially when viewed on a very high resolution monitor.
When you are building the presentation slides, set your PC screen resolution to a lower setting than you normally use. 800X600 should work well and may be the smallest screen size allowed by your video card.
Slide Page Aspect Ratio
The width to height ratio of the default PowerPoint page is about 5X4 (10X7.5, actually) while standard video is 4X3 and "high def" or wide screen video is 16X9, both of which are supported by YouTube and most other web video services. In pixel terms these are 640X480 and 1280X720.
If you are using a screen resolution of 800X600, in PowerPoint use the controls under File->Page Setup to reset the slide size to 5 inches wide by 3.75 inches high for standard video and 7 by 3.94 for high def. This will allow you to see the slides in the PowerPoint work window at 100% of their size for most accurate viewing while you work.
Many fonts that look crisp and clear on your computer screen may look fuzzy or even be unreadable in video. Using some serif fonts (ones with little hooks on the ends of the letters, like Times-Roman) may result in some of the serifs being shown and others not. Some sans-serif fonts can have problems, too, like straight horizontal lines disappearing and curves looking jagged.
In general, you will probably get a consistently more readable result by using san-serif fonts and ones where the thickness of vertical and horizontal letter elements are about the same and where the letters are not excessively taller than wide.
Type effects like bold, underline, italics, accents and the like, can be especially problematic in some fonts, even ones which otherwise might look fine in video. Use them sparingly and do not select your typeface until you have tested it with the type effects you plan to use.
Stylized fonts, like ones that look like handwriting, calligraphy, movable type printing, poster lettering, etc, can look great on one screen and lousy on another. Avoid them if you can or use them only for large title graphics.
In some fonts, small sized letters might be unreadable or even disappear, especially on a high resolution display and too many words on a slide will make it cluttered and confusing. Your production mantra should be, "Fewer words, larger letters." A single text slide should only have 20 or 30 words at the most with none of them in less than about 20 pt. type.
Finally there is the matter of font color. The letter color the viewer sees might be very different than how it looked on your screen, not just in terms of tone but also of apparent brightness, and your choice of background color may make these problems worse.
In my experience, black and dark blue look best on light backgrounds and cyan, yellow and white look best on dark backgrounds.
In short, when it comes to fonts, use simple, solid-looking typefaces and test your choices all the way through to video displayed in a browser at all the font sizes in all colors you intend to use before you start building the slides, and have other people test it on their systems, especially over a mix of PCs and Macs and on a variety of screen sizes and resolution settings. The more the better.
Never use artistic backgrounds, like textures or photographs. They will likely make text less readable and might induce annoying strobing or moire pattern artifacts on the viewer's screen.
If you are going to show your video on YouTube's default display environment, which uses a white background, especially if your slides contain a lot of text, you should use a light color or white for your background (and dark lettering of course). This is because, the brightness of the default YouTube screen forces the viewers' pupils to contract, which will make it hard for them to read light text on a dark video background, which will make them want to dilate.
If your presentation contains photographs that do not fill the video window, you should consider a dark background color instead. This is because in a photograph surrounded by white, it is harder to focus on the details in the picture.
You might think it is boring, but, especially if you are not certain about what the surrounding background color will be in the site where your video will be viewed, use a neutral gray background.
If you are holding on to the idea that meetings have to be held in a conference room, it’s time for you to reconsider. more