Monochrome or Colorful Icons for the Toolbar of a Desktop Application?

Question

I'm going to create a new icon theme for Libreoffice (a word processing application that runs on Windows, Mac and Linux), but I still need to make some decisions regarding the style of the icons. The biggest question I have right now is should the icons be monochrome or should they be colorful?

Here's an example of a monochrome Libreoffice icon theme (The default Sifr icon theme) :

The advantage of monochrome icons is that they usually have good visual uniformity and the lack of color keeps them from being distracting. Monochrome icons are also used in Google Docs and are encouraged by Google's Material design and the Windows 10 UWP design.

Here's an example of a colorful Libreoffice icon theme (The elementary icon theme):

The advantage of colorful icons is that because they are colorful, the color gives the user an additional context clue for them to be recognizable. The icon set in Microsoft Office contain some colorful icons. Colorful icons are recommended in the HIG guidelines for Windows 7 and the HIG guidelines for OS X.

I'm leaning towards using flat colorful icons. Thoughts, suggestions, questions?

EDIT: I found this article which discusses this issue, using Libreoffice as an example.

Answer 1

It's a close call, good question.

You have to choose between supporting the primary task (writing) by not distracting attention using monochrome icons and making the secondary task (format text) easier to search.

In my opinion, it's easier to visually search between colorful icons and choose your formatiing option. However, it deemphasizes the primary task of writing a little bit. I do not know for an existing research on how often users use the icons to format text as it will be useful so you can weight the differences.

If I were to choose I would go with monochrome to gain better support for the primary task by not distracting the attention. Another argument for monochrome icons is that Google advices to use them. Everybody knows that Google are usability frontiers and they make their decisions basen on tons of quantitative and qualitative data.

Answer 2

Who is your target audience, and how do they react?

Color helps some people, but hinders others. In my experience, men tend to register color less than women, even allowing for the 10% prevalence of some form of color blindness in men.

Left to their own devices, I find that men tend to use geometry and labels to organize work, while women are more likely to use rich color coding.

An extreme example of this disparity was a CICS screen designed by a woman for a particular man to use. She had designed the alert for his attention as red text on a green background (the green background meant one thing and the red text meant there a problem). He was red green color blind,so all he saw was a yellow bar when that was the exact thing he needed to know.