Visual Design: Slides Should Be Simple


When I learned that I would have a few very special guests attending my visual design lecture this month, I redesigned my lesson plans.  While these lessons aren’t quite Slideshare-ready yet, I would like to share them with you over the next few days.  I promise to debut the new visual design Slideshare presentation before the end of January!

The new lessons focus on teaching my students 7 key rules for effective slide design.  Read rule number one: Slides Are Not Documents and rule number two: Apply The Picture Superiority Effect.  Today, we discuss rule number three:


Slides should be well designed and serve as visuals as opposed to documents.  Slides should also be simple.  Nancy Duarte refers to slides as “digital scenery,” and this idea will help us to understand the purpose of slides and the needs of our audience.

The idea of simplicity boils down to two major design rules: the three second rule of glance media and the signal to noise ratio.  The three second rule explains that slides are glance media – just like a billboard or an ad in the subway.  An audience needs to be able to glance at the slide, process the message of the slide in three seconds, and direct their attention back to the presenter.


Since we’ve already made the distinction between a slide and a document, we know that 30-50 words on a slide is not effective.  But just how many words should appear on one slide?

A great rule of thumb is to use the three second rule of glance media.  Include a single main idea on your slide.  Step back and count to three seconds.  Can your audience read and process the message in three seconds?  If so, you’re on the right track word count wise.  But if you’ve spent your entire life treating slides as documents, you might need to work a bit to reduce the text on your slides.

One amazing trick I’ve learned is to just add more slides.  If all of the words you want to use can’t fit the three second rule, create additional slides to hold that information.  As a wise slide designer once taught me, an extra slides costs nothing.

Your ultimate goal is to include one main idea per slide.  To get there, make sure that main idea is digestible within three seconds.


While you’re thinking about text on a slide, it’s important to determine what kind and how many fonts to use.  Simple typefaces are key, and I only use free, Commercially licensed fonts.  A great website to download fonts is Font Squirrel.  The fonts I’ve used for my slides in this post come from Font Squirrel: League Gothic (all caps) and Blackjack.  My general rule of thumb is to use one font consistently on every single slide.  This helps with the unity and flow of the presentation.  However, it’s also nice to have one highlighting font just in case you want to make certain words stand out.  The experts agree on limiting yourself to two fonts on a slide or in a slideshow:

Garr Reynolds says, “Use the same font set throughout your entire slide presentation, and use no more than two complementary fonts” (Source).

Nancy Duarte says, “It is best to combine no more than two fonts per presentation” (Source).

Ethos3 says, “We understand the need for more than one [font], but if you find yourself using three or more, you may be flirting with a readability disaster” (Source).


The picture superiority effect teaches us that a large, clear image is key to a successful slide because people remember pictures more than words.  We already know how to search for and select effective images, but how do we know how many images to include on one slide?

Slides should be simple, and one main idea per slide reinforces that simplicity.  When you are designing a slideshow, pair a bit of text with a strong image.  However, one main idea per slide doesn’t necessarily mean one IMAGE per slide.

If you have multiple images that communicate the same main idea, arrange those images using a grid.  Remember to arrange images in a clean, seamless fashion… Do not stack images on top of one another.  Think about your slide as a puzzle where all the pieces must fit together neatly.  In Keynote, using the “Shapes” tool can help you with this task.  Chiara Ojeda shows you how to arrange multiple images on one slide in a clean, simple way in “Build Your Presentation Design Muscle.”  Check out the “Eat Fresh” slide: multiple images, one main idea.

The three second rule of glance media combined with the one main idea per slide rule will help you to determine if you have too many images on one slide.  Since an extra slide costs you nothing, you can always divide your images onto multiple slides.  A deck doesn’t have to include 10 slides… You may need 20, 30, or even 60 to get your message across clearly!


None!  I tell my students they should not use animation on their slides without my permission.  Animation should be simple, elegant, and natural.  Most animation, whether it is a transition between slides or animation of elements on a slide, is tacky and hideous.

If I see animation on a student’s slide, I ask, “What is the purpose of your animation?”  Usually, the answer is, “Because it looks cool!” or “Because I want to grab my audience’s attention!”  You shouldn’t rely on your slides to keep your audience engaged.  That’s why we work to build strong content.  If your flames transition is the only thing keeping people engaged, your content and delivery must be terrible.  Instead of gross animation, just add an extra slide and “build” in additional elements that way.