Cesar's was the best Joker. All the rest after that just crap.

I thought his guise was when he wore that purple mask over his eyes!

The powder was just his guise. I distinctly remember one episode of Batman where The Joker was feigning another person and his face was normal. He was actually called Mr. Whiteface.

I loved his Joker. One of the great things about that campy but delightful TV show!
http://www.youtube.com/watch?v=9gCBiJ3QJnk&feature=player_embedded

The joker in the comic books was mean, lean and green. When I saw Romero as the joker with his mustache still obvious I was disappointed. Only Ledger did him justice much later. But the series was a complete spoof so all of the villains were over the top. Still he was my least favorite.

I consider myself fortunate never to have seen any of the "serious" movies that might have made me question anything about the TV series.

Everyone is very preoccupied with the back-story & psychology of the joker character, why can't people just say "okay, he's obviously a bad guy painted up like a clown? People, switch your analytical brain off & enjoy the show FFS. The comics, & TV series were written to entertain not study! For me, what makes the joker isn't just the make-up, it's the voice & Cesar nailed it. RIP Butch x

His look was supposed to be permanent.
In the first episode he appeared in ("The Joker is Wild", it opens with the Joker escaping from prison. While in prison, he has his trademark white face, green hair and red lips. I think that the shots of seeing normal skin tones were simply accidents where the camera caught parts of Romero that weren't covered by makeup.
The thing to remember about the Joker is that at that time -in the comics- he was portrayed as a clown (His look was permanent, which was established from the earliest stories and confirmed when the Joker's origin was revealed in "The Man Behind the Red Hood", in 1950.) who committed extravagant crimes. He wasn't a homicidal madman at that point. His crimes were mainly done for profit and when captured he was sent to the state prison rather than an asylum. (Arkham wasn't introduced until the late 1970's). The Joker's first stories (in 1940) showed him as a cold-blooded murderer and jewel thief. He later evolved into a clownish thief who generally didn't kill people in his crimes. It wasn't until the 1973 story "The Joker's Five-Way Revenge", in Batman #251, that he was restored to essentially the same character he now is. That story had him as a homicidal maniac who used his trademark nerve toxin among his other methods of killing and was incarcerated in an asylum for the criminally insane.
So, Romero's portrayal of the character was actually a fairly accurate representation of how the Joker had been shown in the comics since the late 1940's/early 1950's. What's more his look was really good (aside from the mustache showing itself) and you could tell that Romero was having a ball playing the role.
Actually, there was one other villain who had some sort of backstory. In the first episode with Mister Freeze, Batman remembers that in an earlier battle, Freeze had -while committing a crime- fallen into a vat of coolant that required he live in subzero conditions. Again, that was more or less Freeze's backstory until
Batman: The Animated Series
gave a the character a new origin tale that was so popular it was retconned into comics continuity.

I grew up with the show as a kid when it aired in my area in the late 70's. None of the Villains including the Joker had an origin story. The only one who came close to having one was "King Tut" who was an archeological professor who turned into the super villain whenever he was struck upon the head. All the other characters including Batman and Robin were just there and it is never explained why or how they became what they are.
Since The Dark Knight came out, it is amazing how many people are tying to compare that movie to some cheesy TV show from the 60's which was mostly meant to entertain little kids.
However, Cesar did a good job with his Joker. His character was one of my favorites. Like someone said, he was just a guy dressed up as a clown who committed extravagant crimes. There is no "dark back story" or anything.

I don't think you should bother asking a question like that about the old Batman show.

He wasn't permawhite / bleached in the TV show. You can see his wrists + neck are normal colored numerous times in the episode.

Well one thing that has to be taken in to account is that the "knocked into acid" version of the Jokers origin was established in 1952 in Detective Comics 168. The Killing Joke one shot gives you a very good idea of how the joke was before and after the incident.

he was a freakLIKE ME!well not reallydunno mate, im guessing he was more of a circus clown that dabbled in crime. i doubt very much they concentrated on such things as origin

hmmm - since this series was sooooo absolute serious and in no way meant to be absolute ridiculous I think the makers of the 60s Batman wanted to be the Joker as "absolute"