so what color is the lazarus pit? I mean, i know that its generally accepted to be green, but in UtRH it looks yellow? it was yellow in tower of babel too, i think.
There are many Lazarus Pits of many colors! There's plenty of variation in the red/orange/yellow/green range.
So green isn’t a totally invalid color, but it's just blatantly false to claim all Pits are always green. Indeed, most are orange/gold.
Considering that many different Lazarus Pits have appeared in canon, multiple colors aren’t a contradiction. And I'm not sure how often we've seen the same pit colored multiple ways, but I wouldn't even consider that to be a contradiction since...it's magic goo. It can change colors if it wants.
The first ever appearance of a Lazarus Pit (located in Switzerland) is in Batman #243, from 1972. It’s sort of a dark teal with green smoke?
1981's Batman #335, shows a different pit on Infinity Island that is orange.
1986's Batman #400, we find yet another pit in Gotham that's bright yellow.
The three issues above are from an era with a more limited color palette available to comics. For more modern references:
The pit in 2000′s Tower of Babel (this page from JLA #46) is red-orange.
2001′s Birds of Prey #34 sees Dinah Lance healed in a yellow-orange pit. In 2006, Cassandra Cain is resurrected in Batgirl #73 in an orange pit that might also be on fire?
Jason Todd was resurrected in a gold/orange pit. Top three panels are from Batman Annual #25 in 2006, part of the Under the Hood arc. Bottom panel is from Red Hood: Lost Days #1 in 2011, and totally matches.
Batman: the Resurrection of Ra’s al Ghul in 2008 shows the only lime green pit I can think of off-hand. This panel is from Nightwing #139.
And in 2010, Kate Kane is resurrected in another orange/gold pit in Batman and Robin #9.
No pics, but in the New 52, Red Hood and the Outlaws #0 shows Jason being resurrected in a green pit in the new continuity so...I guess the entire source of this is people only reading the worst comics. (brb back on my ‘jason fans please read a decent comic’ hill.) And then a number of animated adaptations ran with the Pit being green, and now fans everywhere are convinced that’s universal.