There was an episode of Star Trek: Voyager where 3 Qs appeared before Q and they were all (except Q) dressed in the exact same judicial robes Q wore in TNG’s pilot.
Because they were performing the roles of judges. The Q seem to be a lot more fascinated with humanity than they let on. Or they did it for cameras that documents every mission. (It’s cannon: Star Trek III anyone?)
Or if you believe in the Literary Agent Hypothesis: everything onscreen is formatted for our benefit, and is a retelling of what ‘really’ happened.
yeah i stumped you all, i think ill have to end up writing john delancie!
the explanation about the judge costume makes sense tho but it seems to me that he probably looks more like a regular human in the earlier episodes but moved towards the darker skin / low oxygen level look in later episodes. like maybe towards voyager
this is a pic from ‘all good things’ that kind of describes what i am talking about, with his skin looking darker and his lips looking purplish/black
it is john delancie out of the make up chair, which would kind of imply that the people who associate the appearance with the judge costume are correct
http://www.trekmania.net/conference/behind_scenes/TNG_johndelancie2.jpg
this is a clip from q from death wish, part 3 of 5, a voyager episode.
q’s lips and overall face tone looks darker.
I get an “access denied, theft of bandwidth is a crime!” using your link. Do you have to be a member?
“image and bandwidth theft is a crime” ooooh I’m gonna tell on you.
sorry. okay. i guess that website is picky try this link
http://www.trekmania.net/conference/behind_the_scenes_2.htm
scroll down to the bottom of the page
the picture im talking about is titled
John delancie (during the making of all good things…)
it shows him with his Q make up on real good
Compared to his natural look (which, in the link you gave here, is just to the left), the makeup definately darkens his lips, as well as using mascara.
I presume they want his lips and eyes to stand out more… maybe. He can do a mean smirk, which would explain why they may want to make it easier for the camera to see.
I have been wondering for years why he has blue lips. I just watched TNG episode"Q-Who" and it looked like he had flesh colored lipstick on. Like maybe they were trying to cover up his blue lips.
I believe that honor goes to the skant.
Coincidentally, I saw “Q-Who” and “Death Wish” both last night on TV (it was a slow night), and in both, John de Lancie’s Q and the other Q both had slightly bluish lips.
yeah theres gotta be an explanation in the tv’s star trek q bible / writers guide.
two words.
Casting couch 
I was watching Voyager’s episode “Death Wish” and just got tired of always wondering why The Q’s have blue/purple lips so I asked the question in Google and these forums popped up and you guys appear to be wondering the exact same thing. It’s like they’re suffering from a lack of oxygen or asphyxiated or something. Pretty weird.
My guess is that it started out as a tradition based on the judges’ makeup, and then became extended as a way to identify the character as alien.
It’s just like Deanna Troi’s purple eyes or Spock’s green-tinted skin. Most people seem to not notice, but it does seem to subconsciously make them seem more alien.