User Interface

Chromatabs

Chromotabs is an experiment, by Justin Dolske, in trying to harness the our ability to differentiate and pick-out colors quickly to help us manage tabs. The extension colorizes each browser tab to provide a strong visual indication of the site it represents. Here’s a screen shot of it in action:

You can download Chromatabs here.

It should be noted that this experiment has been retired, and is no longer under development. Read on for the theory and conclusions.

Theory

Let’s first take at the fundamental principle of why colors are useful. In the image below, try to do these two things:

1. Find all the red letters
2. Find all the K’s

You likely found the first task an order of magnitude easier than the second task [1]. This is because of difference in the way our visual system processes color compared to the way that it processes shapes. You can view all of the red letters with a single glance, or even spot them with your peripheral vision. Finding all of the K’s requires a close visual scan.

What does this have to do with tabbed browsing? Well, tabs use the same two visual variables (color and shape) to differentiate themselves from each other. Favicons provide a small amount of color, and the title text of the page consists of a series of shapes. Unfortunately some sites don’t have a favicon, or the favicon they do have isn’t sufficiently unique. Without favicons, you have to do a visual scan to find the correct tab — you can’t spot it with your peripheral vision.

This problem has attracted some interest from the community already. Many of you may be familiar with the popular Firefox extension Colorful Tabs. Its solution is to simply assign each new tab a color from a fixed list, in sequence. First example, the first tab will be blue, the second is yellow and the third green. The tab remains that color until it is closed. Each time you browse the web, you’ll have to remember what a particular color means at the moment:

Chromatabs’ approach to coloring tabs is different. Instead of assigning an essentially-random color to a tab when it is opened, a color is derived from the site currently loaded in the tab. For instance, this means that blog.mozilla.com will always be red, and engadget.com will always be purple:

So, how does it do that? It takes the hostname from the URL, converts it to a number via a simple hash function, and then uses the number as a hue in HSL colorspace to obtain a final color. Justin has a blog entry discussing this and other technical details of Chromatabs’ operation in greater detail.

By keeping each site’s tab color consistent, the user can build up a mental model of what colors are associated with their favorite sites.

Conclusion

Helping to ameliorate the problems that arise from trying to manage numerous tabs is difficult. Chromatabs was one attempt at a solution. There are a number of directions someone could take this prototype to improve it. As a Labs project, however, it is retired.

Possible Improvements

• It might be more intuitive if Chromatabs analyzed each page to determine the most prominent color on the page, and then used that color for the tab. You would then see Slashdot tabs in their distinctive green, Fark tabs in purple, and Zombo.com tabs in, uhhh… oooooo….
• Unfortunately not everyone likes rainbows and unicorns. In the process of converting a domain name into a RGB value, perhaps Chromatabs should also base the color on an aesthetically pleasing color pallet. Does anyone know a good algorithm to create beautiful color pallets?
• A similar problem area is coloring groups of tabs. Here the focus would be on coloring groups of tabs in a unique color, which could be ephemeral and not based on the site’s address.
• Give the user greater control over their browsing experience by allowing them to customize the color for a site. This might have some anti-phishing benefits as well (for example, expecting your bank’s web site to have the bright green color you assigned to it).

The Larger Picture

• What if instead of just providing a favicon.ico, Web designers were able to design the surface of the tab?
• What other ways could the browser provide a richer and more dynamic tabbed interface? For instance, Aging Tabs is really creative, bringing temporal information into the mix.

The Chromatabs extension is open source, so it’s a good starting point for anyone wanting to try out their own variation.

[1] From an HCI lecture (PDF) by professor Rob Miller