I am building a cab booking application, and I need to differentiate the various cabs in the vicinity by their age. Age in the sense how long back did they update their current location. If they update their location frequently enough, I need a good green color. But if they dont update for a while, then I need the customer to know that this cab is kind old, and gradually take this cab out of the list.

I have tried color combinations of green (good), yellow (not updated for 5 mins), grey (not updated for 2 hours). But the more I think of it the more I need the age to be subtle, and not so drastic in its colors.

I need shades of green to just pass on the message without giving the feeling of "oh my god, so many old cabs on the system". I hope I am clear. I need help to decide what shades of green can I use for this purpose. I have thought of these color shades

339900 66FF00 66CC00 33FF66

  • This sounds like a question for Graphic Design (graphicdesign.stackexchange.com) rather than UX.SE. – Matt Obee May 2 '13 at 8:06
  • It is a UX question if there is possibly a problem for colorblind people. I am pretty sure there is. – Gildas Frémont May 2 '13 at 8:09
  • Yup, this product needs to support colorblind people as well. – Siddharth May 2 '13 at 9:06

Colors don't do a number of things very well even though people think they do. Colors don't have an inherent value, they don't mean anything, by themselves. Except for red which usually maps to "bad" and green which usually is "good", but you can still use red as an indicator for anything else. And it's probably fine to use green in your situation, especially if newer = better = greener.

Since the values you're indicating are on a scale, it makes sense to use colors that are also on a scale. I.e. it wouldn't make sense for purple to be on one end of the scale and yellow on the other.

You do need to watch for contrast though. Bright shades of green don't do well on a white background. Also, a lot of people are color blind and it's quite common to not be able to distinguish green very well. Therefore you need to make sure the value of each shade you're using is different enough from the others. I.e. if you completely desaturate the shades they should still clearly be different from each other.

You could use (HSV):

  • 100 100 20
  • 100 100 40
  • 100 100 60
  • 100 100 80


  • Good answer, although I would also want to say that even Red and Green don't always mean the same things across cultures. China takes Red as meaning 'good luck and prosperity', or it's also associated with Communism in Russia for instance. Know your target audience when applying meaning to colours. – JonW May 2 '13 at 8:49
  • Ah, yes of course that is also true. – Koen Lageveen May 2 '13 at 9:00
  • I guess I'll stick to green, and the shades Koen mentioned are good. Thanks again. – Siddharth May 2 '13 at 9:08
  • Glad to be of service ;) – Koen Lageveen May 2 '13 at 9:09

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