In a comment to my answer on this question, Arda Xi mentioned that there is a lot of blue/orange symbolism in Portal 2.

I haven't finished the game yet, but I'm curious. What do the portal colours symbolize?

  • I think this question would be better phrased as "What is the blue/orange symbolism in Portal 2?", since the portal colours are likely only a minor factor in that.
    – thedaian
    Aug 21, 2011 at 14:57
  • 2
    Well, my guess would be the same as the existing answer: They're two distinct colors that contrast nicely and symbolize jack. The teal & orange tag team is not exactly uncommon.
    – a cat
    Aug 21, 2011 at 15:01
  • @lunboks In origin, yes, but there are a lot of examples of them using the difference in the game.
    – user56
    Aug 21, 2011 at 16:05
  • Red and green = Christmas, yellow and purple have notably different luminances at similar saturations, but blue and orange (usually shifted to yellow-orange and blue-green) match well.
    – Nick T
    Aug 21, 2011 at 17:26

3 Answers 3


Note that Orange Blue Contrast is a common trope in media. I'm just listing examples in ways Valve used it here.

I'm only going by my own experience of the game so this is likely incomplete, but there are a lot of noticeable examples of symbolism occurring throughout the game.

Note, the following is going to contain spoilers for both Portal games.

Well, just for posterity, the origin of all this is probably the portal gun itself.

The first one was actually in Portal 1, where Aperture Laboratories are very cool and blue, while the behind the scenes bits after the last test chamber have a more warm, orange feel.

The really obvious ones:

  • The gel colours
  • The co-op robots
  • The excursion funnel (blue when pushing, orange when pulling).
  • The checkmark/cross signs that show the status of an objective

The most obvious one would be GLaDOS, having an orange eye, and Wheatley, having a blue eye. This is later repeated in the end scene, where regardless of what portals you shoot, the one in Aperture Laboratories (where GLaDOS is in the end) is orange, and the one on the moon (where Wheatley is) is blue.

As with Portal 1, the Laboratories are cold and blue, while old Aperture with Cave Johnson has, again, a warmer, orange feel to it.

A more subtle example was in the end speech, right before you were sent up in the elevator. As you can see in the video below, the moment GLaDOS says she deletes Caroline, a bit of warm light that was in the room is dimmed, making the entire room even more blue.

This is all I can remember for now, I'll add more to it as I find them again.

  • So you've done a good job of showing examples of Valve using orange vs. blue contrast for something. But what did they use them to symbolize? Aug 21, 2011 at 16:33
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    @StrixVaria Mainly contrast between Wheatley and GLaDOS, as well as the more human touch of Aperture Science Innovators and Cave vs. the cold, technological Aperture Laboratories.
    – user56
    Aug 21, 2011 at 16:34
  • Note to fireDude67: I intentionally did not use spoiler tags because the entire answer is a spoiler. It's a bit superfluous.
    – user56
    Aug 21, 2011 at 16:37
  • 1
    @Matthew good/bad and orange/blue (or vice-versa) is a very poor correlation. Orange generally suggests warm or earthy, and blue: cool, sterile, clean.
    – Nick T
    Aug 21, 2011 at 19:28
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    @Nick T — Even that isn't a good match (at least in Portal 2). I wouldn't call GLaDOS warm or Wheatley sterile. Similarly, P-Body is animated to feel more fastidious than Atlas. Looking over these examples, I'd say neither color indicates anything on its own — and together they simply represent contrast.
    – Ben Blank
    Aug 23, 2011 at 17:02

I know it's not the answer you're looking for, but blue and orange are two very accessable high contrast colors. Even for the most common forms of color blindness there is never a question of whether a color is blue or orange, it's extremely easy to tell them apart instantly and they're also perfect opposites, making them perfect for "ends" of portals.

  • +1, I remember reading (or listening) about that in either in-game dev. commentary nodes, or in some interview with people from Valve. Sep 7, 2011 at 23:27

I'm going to take a stab in the dark and assume there's a deeper meaning here.


Yellow/red and cyan/blue are considered boundary colours. When you shine a white light through a prism, yellow/red will polarize to one edge and cyan/blue will polarize to the other, depending on the polarity of dark/light.

It actually makes a lot of sense then that two portal colours are orange and electric blue because in "colour theory" they represent two opposite edges of the same plane/surface.

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