When creating a presentation your entire palette will depend on the background color you choose. There are several factors to consider when selecting a background color or a background photo. Nancy Duarte’s book Slide:ology gives a really nice overview on color theory but I felt like a an important component on choosing a light or dark background was left out.
What is the lighting set up of the venue where the presentation is going to be viewed and what equipment is used to view the presentation.
Have you ever tried watching a dark movie during the day, when the TV room is full of light? If there is a light bulb going off in your head right now, you know where I’m going with this. The reason movies look so great in TV theaters or at night, is because the viewing area is completely dark. In case you don’t know what I’m talking about, the answer is that you will see your own reflection in the screen and the blacks will look washed out.
A little color theory to explain this.
When it comes to TV screens, monitors and projectors there are two Color Systems in play. One is how things are actually displayed on the screen, and the other is how the color interacts once it’s displayed and how it will be printed.
How is color displayed: The Additive Color System- RGB
In the additive color system, white is actually what we normally think of light. And light breaks down into a combination of color (spectrum), that’s why we see rainbows http://en.wikipedia.org/wiki/Rainbow. Think about a rainbow, it does not contain black.
Black is simply the absence of light (the reason why it’s dark outside).
Look at your computer monitor when it’s off; it is black. A computer screen or plasma TV screen is divided into a grid of many tiny dots, we refer to as pixels. Each pixel on a monitor has 3 tiny light bulbs in color Red, Green and Blue. Colors are displayed through different percentage combination of Red, Green and Blue, [RGB]. 100% values of all three produces what you see as white, 0% values of all three means the pixel is “OFF” and you see black. You can test this out, by opening PowerPoint and creating a large black square. Stare at it as you turn off your monitor. You will not see any change in that area. This is why when a screen is dark and you turn it toward the light source it’s hard to see, the light is bouncing off the coating of the screen instead of being absorbed. Now your black square will look gray. And you will see a reflection due to the coating on your screen. (think mirror, or seeing yourself in a puddle of water)
Now you might think wait a minute, but I thought primary colors were Red, Blue and Yellow… well you are correct, but that particular color theory applies to pigments, or what you know as paint. Sometimes this is referred to as an Artist’s spectrum. You can use the artist’s spectrum in reference how colors are perceived but not how they are created, or how they interact on a computer monitor.
Overlaying transparent colors over each other in PowerPoint or Keynote simulates a Subtractive color system or CMY[K]. This system is also used by printers. This is why what you see on the screen never looks exactly the same printed. You print on white paper, so to achieve white, the printer doesn’t have to do anything, it uses zero amount of ink and any area of black uses 100% values of Cyan, Magenta and Yellow inks. K (black) was added later to this system as a separate pigment in printers because the pigments in Cyan, Magenta and Yellow couldn’t reproduce a true deep black color. But this will be a completely separate post at some point, as this issue requires explanation and tips to avoid it.
What you should remember from this, is that in situations where the presentation will be viewed in a well lit room, you should be weary of using black or dark colors as the background because they will appear washed out or will create screen reflections in cases where plasma screens instead of projectors are used. Dark background colors are best used in presentations delivered in dim lighting.
The opposite effect should be considered when using a light or white background in a dim lit or dark room. Think of it as staring directly into the light for a long period of time.