Blocks of background colour can help group cognitively-similar items or set off reporting elements like sidebars. Text intended for narrative reading should be set in black or dark gray on a white or very light background.
Colour choices in reports, slides, and graphs should be intentional. Too often the colour scheme is the default one chosen by our software program. But colour changes indicate meaning changes to our readers, so we must be thoughtful about the use of colour. Given that, you have many colour choices.
An action colour can draw attention to key parts of your reporting. Use it as the background for call out boxes or on an important line in a line graph, for example. Action colours work best when the surrounding information is in grayscale. For example, every bar in a bar graph would be gray, except for the one that needs attention, which would be in your action colour. Because action colours draw the viewer’s eye, only apply them to things that really need focus (not, say, on the page number).
Colours have cultural meanings associated with them. While tricky to navigate, this can work to our advantage when reporting. In many cultures, red is considered a warning colour, communicating negativity or caution. Blue is often interpreted as a positive colour. Thus, it can be helpful to assign these colours to the poles of a Likert-based stacked bar chart, for example, where reds would be assigned to Strongly Disagree and Disagree and blues would be Agree and Strongly Agree.
Yet another option for colour use is to integrate brand colours from your organisation or your client’s organisation. You may find an organisational branding guide with an entire colour palette already created that can serve your reporting needs. Or you may choose to pull from that palette when selecting an action colour or creating a sequential colour scheme.
Some colours do not hold up well when reprinted in black and white. Test a critical page or two by printing it in black and white and then making a black and white copy of that printed page.
Also, be cautious of using certain colour combinations that may be undetectable for people with colourblindness. Red-green and yellow-blue are two combinations to avoid.
ColorBrewer allows you to explore colour schemes that are colourblind safe. You can select diverging or sequential schemes here.
Adobe Color CC (formerly Adobe Kuler) is useful for generating colour schemes from screenshots of, say, a logo or photograph.
Please: don't use default colors in your chart: Ann Emery models the use of different colour choices in this blog post
The ROMA Guide to Policy Engagement and Influence uses a well thought out colour palette to organise each section of the guide.
This report on The Role of Monitoring and Evaluation in Evidence-Based Policy Making has a colourful cover but makes smart use of nothing but shades of gray in the interior pages of the report.
Our own guide to using the BetterEvaluation framework is another way to use colour to help sort content for viewers. We used colour in this handout to group the material into sections.