The two main uses of color that we covered so far are using color to encode information about quantity, for magnitude representation and sequence. And we also covered the idea of using color as a way to categorize or label data according to a number of categories. And we also saw that there are a number of methods to create effective color maps or color scales to represent color for these purposes. Now I want to introduce one third purpose of color, a third way color can be used effectively in visualization. And this is about using color to highlight or emphasize something in a visualization, which is also very very useful and very important if used appropriately. Let me give you an example, I want to start with this example. So this is a visualization developed by Gregor Aisch for New York Times. And the idea here, there are a number of different countries. And what you see on the x axis of each of these countries is a number of years. And what you see on the y axis, there is a proportion of different types of parties. But the article that actually comes together with this graphic is about parties on the far right and their prominence over time, whether they're growing or shrinking across different selected countries. Okay, so now since the article focuses on this topic. What you really want to focus on in the graphics, what you want to see, what the author wants to communicate is actually what is the main proportion of far-right parties. And that's the reason why this segment is the only one that is colored, and it's colored with a very intense red. So the rest is still visible, it doesn't mean that the rest cannot be seen, but it's grey, it's on the background. And the only thing that is colored is the one that the author wants to highlight or emphasize. And as you can see, it works really really well. So the best way to highlight with color, or one of the best ways to highlight with color, if possible, is to use different shades of grey for what is not the main piece of information that you want to communicate, that you want to keep as a background. And then use something that is colored, so that it stands out compared to the rest. Let me give you a few more examples. This is another visual representation, another visualization that has been created by Moritz Stefaner. And in this visual representation, this is a scatter plot, where what is shown is different countries and in terms of fertility rate and life expectancy. And these lines that you see are basically the same country, how the value changes over time. And as the time changes, the bubbles also go from small to big. You can see in the legend on the top right, what is the relationship between size and years. So starting from where it's very thin to where it's very, the border increases, you can basically see how it changes overtime. But that's not the main purpose, the main reason why I'm showing you this visualization. But I'm showing it because it's another example of emphasizing, attracting the reader's attention using color. So here, what the author decided to highlight is two main countries, United States and Vietnam. These are the only two countries that are colored, and the rest is gray and is in the background. Okay, why? Well, because the idea here is to emphasize how much Vietnam has progressed compared to United States over a certain number of years. So that's the main communication intent behind this graphic, and this is why these two elements are highlighted. Here is another example that shows the same principle. So this is abortion rates across a number of years and for different age ranges, going from left to right. And again, so every single line that you see there is one of the range ages that are repeated across all charts, but those that referred to the actual bucket, to the actual range, are much more saturated. So you see the orange one is the one that refers to the age range. And the dark gray one that is repeated across all of them is the average across all of the ranges. So once again, color can be used as a way to highlight some elements of interest and direct the reader's attention to something that is supposed to be noticed. And the use of gray in these cases is also very useful because using gray to give color to the rest, so you don't have to get rid of it. But it also doesn't interfere with the main message, and provides useful context is also very very useful
