I love hearing or reading about how creators go about making their comics. There's always something new to learn or a different way to approach a problem. And without fail, in all the panels and interviews and Reddit AMA's, there is one question that comes up repeatedly, and that is:
"How do you know how many panels to put on a page?"
It's a problem that's burning in the hearts of every would be creator, and like most things, there's no simple answer. Sure, most people agree that 5 or 6 panels is the most you can fit on a page without things getting messy, but now you're thinking to yourself "but Watchmen - - " Stop. Don't finish that thought. Never finish that thought. Instead let's talk about a few ways we can approach panels.
I'm not going to get waist deep in Scott McCloud's Understanding Comics, but let's talk about the idea of completion. Basically the way your brain fills in the action between one panel and another. As a writer, your goal should be to fit the most story into the least amount of space. That's because space is limited. Most Marvel and DC comics range between 20-22 pages. Independent books you get a little more wiggle room, but because you have that space doesn't mean you have to use it.
So with that in mind think of a page as a scene of a play/movie/T.V. show. In all those mediums, time is measured by...well time. Seconds, minutes, the like. With comics, time is determined by the the reader, I.E. how fast they read. Now you as a creator can't necessarily control that, but you can dictate it in a way by the amount of panels you use per page. Now this is where completion comes into play. Pull up a scene from a movie or show you like on Youtube, and watch it one time. Now watch it again, this time making note of what you consider to be the key parts of the scene. Now using those key parts, see if you can translate it into a comic page. Now, see if you can remove even more and still make it work. Basically you want to try and distill it down to the most essential elements. This is should be your goal with every page.
I can see the scenes in my comics pretty clearly in my head like a movie, so mentally I'm watching each scene play out, and then "pausing" on the most exciting or interesting or necessary parts. This might not work for you, so instead maybe try acting it out. I know it sounds and will probably feel silly, but you chose to be a writer and sometimes that's part of the job. Whatever way works for you, use that to try and find the most essential parts of each scene. And be honest. You're going to have plenty of ideas that are cool or exciting or "lit" as the kids say, but are they essential? If you can remove it and the scene still makes sense, then lose it, no matter how awesome it sounds.
Let's expand on the idea of time briefly as well, because it's another thing to take into consideration with panel count. The more panels the longer it takes to read, and the reverse is true with less panels. So what's this page about? And how do you want someone to read it? It could be a fight scene or it could be a conversation between two characters. Take a second to look at these pages.
So what do you think? Each of these pages has different intentions, a different number of panels, and different layouts. How long did it take you to read each of them? The Alias page has a lot of dialogue, and is spread out over two pages, and probably took you longer to read. The Moon Knight one is interesting because it's only three panels, but you can read it a couple different ways. Because the last two panels don't have dialogue the reader is free to spend as much time on them as they choose. The Batman page also has some variety. The dialogue is short and punchy (pun intended) and moves along quick, but the action is slightly deconstructed and has a flow to it. You're supposed to take it all in. Each punch and kick at it's own pace.
So right now you might be thinking, this a lot of stuff to keep in mind, and yeah at first it can be. But the more you write, a lot of this will start to come naturally. You'll get a feel of how many panels are needed for certain things. That's why I choose to answer the question of how many panels should you put on a page with "well how many do you think you need?" Just keep in mind that the more panels on a page, the less space for your talky balloons and boxes, so if you're going to write a whole monologue, you'll need to cut down on the panel count. Again, look at how Bendis is able to fit in a whole bunch of dialogue in what amounts to just 7 panels.
That feels like enough for now. Try out the exercise I mentioned above and see if you can start to get a feel for how many panels you'll need on any given page. There's a million articles out there on layout and repetition, rhythm, etc, and I'll be sure to post some of them, but that's a different subject entirely. I'll be back soon to briefly touch on do's and don'ts for panel descriptions as well as pacing and then we'll move into formatting your script. Until then, go make some comics!