'Superman IV' was filmed entirely in England. Visual effects supervisor Harrison Ellenshaw told 'Starlog' in 1987, "We're filming in England because there is a cost difference, but more importantly, we don’t want to mess with the formula. They did the first 3 over here (in England), so why fix it if it isn't broken? That's part of the reason we're standing here, freezing to death."
Back in 1979, director Richard Donner declared, "Tom Mankiewicz is solely responsible for my 'Superman' script, as far as I’m concerned. He took a great outline by Mario Puzo and a good script by Robert Benton and Leslie Newman and then created a different aura. Writing-wise, he interpreted it totally different and made it better. That’s not to knock the other writers, but Guy Hamilton had a different approach than I did. The original was a different form of reality. It even had Kojak in it."
Christopher Reeve added, "In the original script, Superman was looking for Lex Luthor when he sees a bald guy on the street. It turns out to be Telly Savalas who says, 'Who loves you baby?' and gives him a lollipop. That was the kind of style that had to go. Puzo had done a beautiful job, but Mankiewicz cleaned everything up. We used his stuff as a guideline, then all of us improvised the new dialog on the set. The writers squirmed; that’s what we had to do.
"I suggested that the ending that you see be put in. It was based on a suggestion from Richard Lester. He said, 'You’ve got to have the protagonists go through some heavy stuff.' And I felt that Superman had to have a fallibility if his achievements were to have any importance. In the original script, you lose track of the love story. It was just a finale of standard explosions and derring-do. We needed to add a story of humans. I made a decision early on that my characterization of Superman would be so strong that he could be vulnerable; that he could reach out and make a commitment. That commitment has to be tested."
Margot Kidder believed, "Of the first 3 ('Superman' movies), I thought the 3rd one was abominable – it had no heart, no feeling, nothing. The first one was made with great love, and Dick Donner’s respect for the material and lack of fear about being sentimental and having feelings was so obvious through the whole piece – that's what made it his movie. It was a very beautiful, very moving film."
"We got the initial idea for 'Superman III' during the shooting of 'II'," screenwriter David Newman disclosed in 1983. "I remember vividly, we were sitting in Niagara Falls, having a drink, when Leslie and I went off into a corner. Suddenly, we had the beginnings of what the 3rd film was going to be about. At that time, there wasn't anything with Lois (Lane) in the movie because we all felt we had taken that love story as far as it could go."
Producer Pierre Spengler insisted, "There is no 'Tron'-like action. It's not a computer movie." Ilya Salkind elaborated, "We've found new ways to put emotion into the action. There are, I think, some new developments which will surprise many viewers. We're exploring things that have remained unexplored, like the real Clark Kent, and other things like that.
"We're not really being more realistic, and I hate to use the word 'modern', but that's what the film is. On the one hand, you have escapism and adventure. That’s identifiable. You can believe in Superman as Kal-el or when he plays a straight Clark. He’s a fantasy hero who everybody wants to have around especially in these times. As a kid, I reacted the same way." Clark Kent from Smallville graduated from high school in 1965.
In 'Superman II', "We had 3 plots going simultaneously – the Lois/Clark story, the 3 villains from outer space, and the Lex Luthor story," David stated. "We tried to do that as much as we could in the 3rd film as well. There's a plot with the Richard Pryor character, Gus Gorman; then there’s the main villain, Ross Webster, played by Robert Vaughn; and there’s the Clark Kent/Superman-going-back-to-Smallville-and-meeting Lana plot.
"What’s interesting is that, bit-by-bit, all of these things gradually come together in a way you could not predict. Our Lana Lang is a woman with a child, among other differences. The comic book is going to try and adjust to it. Lana Lang is not in love with Superman, she is in love with Clark. She has no idea that he’s Superman, and couldn’t care less. Lana does get to meet Superman. She thinks he's swell, but it’s Clark who she really loves."
On reflection David Newman made the observation, "One of the things which has always fascinated us (David and Leslie) about the character is Superman's schizoid nature (split personality). Clark Kent was always the poor schlep who had to take a back seat to the exploits of Superman. We’ve always believed that in some kind of funny, crazy way, Clark Kent doesn’t entirely like Superman. He resents the fact that only part of him gets all the plums in life."
"I had only read a very rough first draft (of 'Superman IV'), which was OK, but I hadn’t read the draft we have now," Margot Kidder made known in 1987. "I mean, I like the script. I just think it's so brave to make a 'Superman' movie with an anti-nuclear message. I can’t honestly say whether kids or adults will accept that, but I think it’s one of the nobler or more honorable ways to use an audience as large as the 'Superman' audience. It’s a cause I’ve been committed to for nearly 10 years (since 1977) - so that was all I had to know."