KNOWLEDGEBASE - ARTICLE #2234

Colorblind safe color schemes and color transparency

Prism 9.5 introduced nine new color schemes to choose from when customizing your graphs. Three of these new color schemes were designed with a focus on accessibility for individuals with various forms of color vision deficiencies (often simply called "color blindness"). Although the colors in these color schemes are generally distinguishable across multiple forms of color blindness, the colors become much harder to distinguish when color transparency is used.

Adding transparency to a color can be useful in a number of situations when multiple objects (such as bars and symbols) overlap or share an identical color, leading to some of these objects being obscured or hidden. Prism will automatically employ this technique for some graph styles to ensure that data objects aren't hidden. This occurs most commonly on graphs with bars and symbols where the symbols and bars would otherwise be the same color. In this scenario, Prism sets the transparency of the bar fill to 50%, allowing the symbols to be seen even if they're located within the bar.

The downside to adding transparency is that it allows more of the background color to "show through" and can change the appearance of the color as a result. In the case of Prism, this background color is almost always white. So adding transparency to a color on a graph will cause the color to appear lighter or more "faded". This can lead to challenges in distinguishing colors for any individual, and can be even more challenging for an individual with a given form of color blindness (depending on the colors being compared).

As a general rule, we would recommend not to use transparency in conjunction with any of the "Colorblind safe" color schemes provided in Prism. Note that Prism may automatically add transparency to color schemes depending on the type of graph selected. To check the transparency of any color used on a graph, start by opening the Format Graph dialog (double click on the graph). Then, find the color and open the color options:

On Windows, open the dropdown menu for the desired color, then click on "More colors & transparency"
On Mac, simply click on the color well which will open the Colors dialog

Be sure that the transparency of the object is set to 0% (on Mac, set the Opacity to 100% as these are equivalent concepts). If you've created a graph with bars and symbols, you can also choose to use a symbol that includes a border color. As long as the border color you choose for the symbol is different from the bar fill color, Prism will not automatically include transparent colors for the bar fills.

Below, graphs using each of Prism's "colorblind safe" color schemes are shown alongside simulations of what these graphs would look like for an individual with various forms of color blindness.

Colorblind safe 2: Sunrise