It's safe to say that 'Zack Snyder's Justice League' is one of those movies that's going to inspire some strong opinions.

So, if you happened to watch it since it was released on Now TV and Sky Cinema here in Ireland, you've no doubt got some questions about it. Is it a part of the DC Extended Universe? No, not at all. Will there be a sequel to it? No, apparently not. What's up with those black bars on the side of the screen?

Well, that's going to take a bit more explaining.

It's to do with aspect ratios. On your TV, there are normally two settings - 4:3 and 16:9. Since practically all TVs today are rectangular in size, 16:9 is the aspect ratio everyone uses. It's 16 units horizontally and 9 vertically. Like a rectangle. 4:3, meanwhile, is 4 units horizontally and 3 vertically. On a TV, that looks like a square.

When Zack Snyder was filming 'Justice League', he shot the film on a 1:33:1 aspect ratio on 35mm, which is similar to the same aspect ratio for Hollywood classics like 'Casablanca' or more modern movies like 'The Grand Budapest Hotel' or 'Ida'. This is called the Academy Ratio, and it's 1:37:1.

As a result, when you play any footage in that aspect ratio on a TV, it looks like 4:3, which is as Zack Snyder actually intended. The movie, in his mind, is supposed to be seen on an IMAX screen, blown up to a much bigger size. In an interview in 2020, he explained his thinking.

"My intent was to have the movie, the entire film, play in a gigantic 4:3 aspect ratio on a giant IMAX screen. Superheroes tend to be, as figures, they tend to be less horizontal. Maybe Superman when he’s flying, but when he’s standing, he’s more of a vertical. Everything is composed and shot that way, and a lot of the restoration is sort of trying to put that back. Put these big squares back… it’s a completely different aesthetic. It’s just got a different quality and one that is unusual. No one’s doing that."

The result of all that is that when it's shown on TV, you get big black bars on the side of the screen.

Still doesn't explain why it's four hours and two minutes long, though.