Colors are a strong medium to convey ideas, feelings and attract/retain attention. The choice of colors in illustrations, presentations, and posters is important. Colors will play a role in the overall interest, output feelings the receiver will have, and even could help the receiver to remember the work and/or the work’s author. But the choice of colors is not straightforward.

Indeed, the effect of your color’s choice will not be directly related to fashion or esthetics but mostly to culture. It is a very well known phenomenon in design and has been studied by scientists: the meaning of colors varies with culture, time and context. Does that mean that you should just go with whatever fit your own perception of colors and personal tastes?

Here is all up to you in fact. You need to decide where the balance between personalizing your work (on your “artistic” side) and following the guidelines (on your “perfect” student/employee side). It also depends on how much you want others to connect to your work, who will see your work and why you made the work. So let’s dive a little bit into that before I give my advice on the subject.

First, if you want others to connect to your work, it is always a plus side to insert your own personal touch into it – because if the work is a result of several previous workers (says you use a template from your workplace),  you will not connect to it yourself and it might be hard to promote it.  Second, you should apply yourself to your public. Since now you know that color meaning is not universal (nor eternal), verify quickly what are the general significance attached to the main colors (primary and secondary colors, plus white/black). For instance, I know that in France, black is often associated with death and funerals while white is for weddings, but, in Japan, white is preferred to symbolized death (not that the participants wear white), and black is common at weddings. Additionally, if your work is for children, companies or a scientific community, it should be clear that the color choice should be adapted according to the general “rules” associated to these groups (note that the “rules” change in time and in place). Third, if you do the work for someone else (your boss, your client, your supervisor…), then you might have to adapt some of your choices accordingly – while you can always justify your choices with argumentation (if your only answer to the choice of “vibrant pink” to your background in your presentation is “I like it”, you will not be able to retain it).

Ok, now, what to do with colors? Fortunately for you, general guide rules can be applied to choose colors for your work:

(1) create your color palette by using a color wheel: if you choose one color, then the opposite color on the wheel will fit quite well with it. You can find a color wheel with a lot of color variations scattered on the web.

(2) in a poster/presentation slides: limit your color palette to 5 colors maximum. An overdose of colors will only confuse your message and might even give a “weird” or “bad” feeling to the viewer. I would assign a maximum 2 colors for background (titles/slide colors) and the rest for objects in the slides. Similarly for a poster. Consider saving ink (always good for the environment) by using a white background for your poster.

(3) in a poster/presentation slides: be wary of too stimulating background colors (or motives) that would overwhelm the viewer and shadow the actual content. Be careful if you choose a dark background to have the appropriate font color. Also, black background will make reading more difficult (but highlight well graphs, images and photos), you might loose people’s interest if they have to squint their eyes to read your text.

(4) in a poster/presentation slides: be consistent in your color’s meaning. For instance, if you assign red for important information, do not use red all other your work! To highlight parts within your work, you can use alternatives (strongly encouraged) like: space (empty space can draw the eye), shape (bigger objects are more visible – though this is not entirely true for all cultures XD), style (for text, bold/italic/underline – for an image, cut in shape/framing…).

(5) in an illustation/ scientific graph: do not abuse of contrasts if you do not have some artistic background (painter, photographer…) & avoid using default choices of programs like Excel or Origin – they are often not well design for scientific publications.

(6) in a scientific graph: I strongly encourage to use a colorblind palette (for instance “Viridis” for R, Python…), mostly if you have no other preference or if this palette fit with your “background” palette.

(7) in a scientific graph: remember that some papers still publish in black & white, so verify if the colors can still be distinguished. For instance, red and blue usually are not.

(8) in my personal opinion: avoid flashy colors in more than very small objects in your work. I know it was favored in the 80s, but the positive connotations (youthful, lifeful, energizing) are all but gone now. And frankly, for science, it should remain for the actual scientific results observed (using a dye for microscopy, plasma sources…), no need to add them to the mix.

If you want to know more about colors, I suggest that you search “color” and “graphical design” on your search engine (or at your favorite library webpage). I attended a course during my Ph.D. (called “Visualize your science”), and I have read several books on design-related subjects.