A big part of what makes us feel like we should laugh at a scene or take it seriously is the visual cues that are used within the sequence. So one of the easiest ways to ensure the audience reacts to your story in the intended way is to use the right kind of visual language.
These are examples from two comedies: "Little Miss Sunshine" and "Nacho Libre".
Bright colors are a good visual cue to tell us that a scene is supposed to be funny. Also, a general feeling of flatness makes a scene feel humorous, and anything you can do to emphasize that feeling of flatness can add to the humorous aspect. Symmetry is usually very helpful to make it feel flat. And if a character is walking, or a vehicle is moving through the scene, it should be moving either parallel to us or directly towards or away from us. That way, it's not creating any depth as it travels through the frame.
By contrast, here are some dramatic scenes from "3:10 to Yuma" (the modern remake), "Touch of Evil" and "The Verdict".
These are markedly different from the comedic examples. Here, the palette is much more subdued - less color makes a scene feel less "cartoony" or gives less of a carnival/circus feel, and makes us feel less like laughing. Also, depth is created as much as possible...there are objects in the foreground, middle ground and background as much as possible. The camera is tilted to create more depth and more dramatic angles. Even when the horizon could create a flat line, the camera is tilted slightly to avoid creating any horizontal lines.
When Charles Schulz first started drawing "Peanuts", he drew with a lot of diagonals and created a lot of depth within his simple style.
This makes sense. In art school we're all taught to create dynamic angles and a sense of depth in our drawings because we're told these things make a drawing better (and they do).
But just making good drawings isn't really the whole point of a comic strip - comic strips are supposed to be funny. And I think at some point, Schulz realized that if he flattened out his drawings, they became funnier.
So flat visuals are great for setting a funny tone and visuals with depth are great for setting a dramatic tone.
For a film like "Nacho Libre", this creates some pretty clear guidelines about how to art direct your movie and set up your shots. The same is true for "3:10 to Yuma". Each film has a clear overall tone and mood that's very extreme and consistent throughout the movie (in one case, comedic, and in the other, dramatic).
But most movies live in the middle of the two extremes. Most films have some serious parts and some comedic parts. So is transitioning from one type of scene to the other awkward and clunky?
Actually, no. Dramatic shots with depth and flat shots with humor can easily co-exist right next to each other. When done right, the audience doesn't even realize the difference. But as film makers, we can use these techniques to create a laugh in the midst of an action sequence to break the tension for a moment before returning to action and drama. And vice versa: a humorous scene can suddenly turn dark and foreboding....and then just as quickly switch back to hilarious.
Here are some screengrabs from the first Star Wars movie, from the beginning and the battle aboard the Rebel Blockade Runner. These shots are actually all right next to each other. Here they are, in order:
Here, in the midst of the battle scene, are two shots with a lot of depth and drama as rebels and stormtroopers battle it out. Then, in contrast to these dramatic and exciting scenes, there is one very flat and comedic scene as R2-D2 and C3-PO travel through the corridor, right through all the heavy blaster fire (notice they are traveling parallel to camera, to give the scene that flat and funny feeling). Then it's followed by more dramatic scenes as the battle rages on.
So within a sequence you can slip from one type of scene to the other, and if done well, the audience won't feel the change of mood at all.
Every scene in my life I've boarded pretty much fits that description; except for extreme cases, most scenes have some dramatic moments of emotion and some moments of lightness. Those are the type of scene I like to board most; I love the challenge of transitioning from one type of moment to the next and finding the right balance of laughs and emotions as well as creating the right staging to get the audience to feel what I want them to feel. I particularly enjoyed that challenge in working on "Tangled"; there were so many great scenes that I felt had a particular challenge in that regard.
For example, the scene where Rapunzel enters the "Snuggly Duckling".
I love the mood of this scene because it's both comedic and dramatic at the same time. It's a scary scene for Rapunzel - this is the type of place and the type of person her Mother has made her terrified of. And yet the scene is funny as well - from Flynn's P.O.V. the scene has a lot of humor, because he doesn't really think they're in danger, he's just trying to trick Rapunzel by playing to her worst fears.
The scene is a delicate balance - if the scene becomes too cartoony and funny, you might think Rapunzel is an idiot for being scared of cartoony clownish thugs and you'll stop liking her. So the thugs in the bar have to convey some real menace.
At the same time, if the guys become too scary or intimidating you can't laugh at them, and there's no humor to the scene.
It was a tough scene to pull off but the artists that boarded it, laid it out and animated it did a great job of balancing the two priorities and making Rapunzel's fright real and sincere so the audience could empathize with her, and not look at her as a clown or see her as someone who isn't very smart.
Also we wanted Rapunzel standing up to them and attacking them as a real moment of heroism and courage for her and something that's hard for her to do. If the guys in the bar come off as cartoony and silly then it's not much of a courageous act for her to stand up to them.
Another scene that I think balances out the humor and drama is when Flynn escapes from prison. It's a serious scene (he's about to be hanged, and that has to feel like a real threat) but Flynn is saved in a way that has humor to it, to keep the scene from becoming too dark and oppressive.
But on the other hand, if the scene becomes too light and fun, you lose the sense that Flynn's life is in the balance and that if he fails in his escape he's going to die. So you can't go too far with the humor.
I think that's one of the big keys to storyboarding a Disney movie: you have to make the threats and the drama feel real enough that the audience really believes that the characters are facing serious issues and a lot of jeopardy. But at the same time, we're not making "Saw" movies, and we need to balance the darkness with some lightness to make the movie palatable to all viewers, and create fun characters that make you laugh and cry so that you enjoy watching them and you enjoy going through their trials and tribulations with them and care whether they come through them (or not) in the end.