Funny, I thought the dog alien in 3 was brown.
If it was I never noticed, I thought it was black, but its down in the lead works most of the time so it reflects the light off its head (which is orange/red lighting). Infact I'm certain its a very dark grey/black, darker than the original. Take a look at the scene where you think its going to kill ripley but sees it has an queen inside her. If memory serves me correctly its all very black.
It maybe a case of the queen reflecting the light from them two whatever they are of red lights, but it seems a bit clean, and the room its in is all neat and tidy. If you look at Aliens, everything is f*cked up and gigerised, its egg laying thingy is all melded to the roof and flaw, the eggs are just everywhere and the queen looks all... well more real.
I think part of the problem nowadays is that cameras are far, far too good. In the eighties they weren't so hot, and I think this held horror films with a dark and gritty atmosphere. Now if you want a really horrid film you need great patience, set design and a decent director to pull out all the stops. With these big budget films you just don't get it, everything looks so clean and I really dislike them for that (a4 included as you might have guessed). Maybe they should ban all these shit directors from using modern tools like CGI and decent equipment?