I read a quote once that I thought was really great, but for the life of me I can't find the source anymore. I know I read it in relation to "Watchmen" (the comic book, not the movie) and I'm pretty sure I read it on the Wikipedia page for the comic...but I don't see it there anymore, nor could I find it on either Alan Moore or Dave Gibbon's Wikipedia page. I'm sure someone has it or can find it and tell us exactly what it was...but to the best of my knowledge, it went something like this:
Gibbons (the artist behind "Watchmen") said something along the lines of: "I don't use action lines to describe what is happening in the frame; I use blood and posture to tell the viewer what is happening".
Now I always like the kind of quote that points out something that's obvious but that I never really thought about before. Maybe the above quote is obvious to everyone else - and, admittedly, I've never been into comics all that much - but I thought it was a cool thing to think about.
Basically, what I got out of it was that in older comics, to solve the problem of indicating what the action is within a static frame, it was more traditional for artists to use motion lines to indicate the movements of the characters.
Whereas (some) modern comics tend to use "blood and posture" to indicate the character's actions instead.
These are from Jordi Bernet's "Jonah Hex" - in his (relatively) realistic depiction of a Civil War-era battle, motion lines are fairly nonexistent, but blood, posture (and other clues) are used to indicate the action.
A drawing by Mike Mignola that has a tiny indication of an action line for the punch's impact...but even without it, the posture would still carry the meaning very clearly.
There's nothing wrong with using motion lines, of course, and many comic artists that draw "realistically" use them in addition to the clues found in "blood and posture".
But it does seem to me that those modern comics that are trying to achieve a weightier, more serious tone tend to eliminate motion lines because it is a bit of a "cartoony" shorthand.
Posture is a powerful tool for us artists, especially here when we're talking about static, sequential art. Posture can tell you all you need to know about what a figure is about to do, what it has just done or what has just happened to it (which obviously is more of a challenge in still drawings than, say, in animation).
The "language of posture" is a universal one - when an artist gets the pose just right, we all know exactly what the figure is doing. So it's clearly hard-wired into our brains. Why, then, is it so hard to learn how to draw figures so that their poses and posture impart their meanings clearly? I wish I knew.
Even the simplest of anatomical clues can give us a lot of information. A head turned sideways - with the neck turned against the shoulders - tells us the figure turned to look at something (see examples 1 and 2 below). We don't need to see the "before" drawing to get that the figure just turned their head to look. Nobody walks around all day with their head turned to the side; therefore this reads as a look over at something important.
Think about the difference between just moving your eyes to look at someone or turning your head to look at them. If you're in a room with some people and you're having a discussion, you're not going to turn your head constantly to look at them as they talk, right? You'll just move your eyes. But if someone starts talking to your left and you didn't know they were there, you might turn your head with a little more emphasis because you're slightly surprised. And if, for example, a loud noise occurs to your left and surprises you, you might turn your head with a lot of emphasis towards the sound while you simultaneously lean away from the source of the sound and duck your head down while raising your shoulders to protect your head and make it easier to flee if necessary (see example 3).
All of these actions would also be affected by the mental state of the figure in question. If you're on edge and tense, your reactions are different than if you're relaxed, or even if you were awaken from a deep sleep, or interrupted while focusing on something very intently. Or if you heard a voice that you didn't expect to hear, or it was the voice of someone you were afraid of (or someone you were just gossiping about or talking badly about) or if it was someone you felt a lot of affection towards...all of these things affect how a person might react and all of these things can be reflected in the figure's posture so that the viewer knows exactly how the figure in question feels about what is happening.
There are an infinite number of other things that can be reflected in the posture of the figure that can indicate to the viewer how a figure feels about what is happening. If, for example, someone enters the room and starts talking, our figure might not bother to turn his head towards the speaker if our figure has nothing but disdain for the speaker (or whatever the speaker is saying) like the figure in example 4. Adding lowered eyelids adds even more of a contemptuous feeling, as does tilting the head away from the speaker (see example 5). Other things like looking down your nose at someone or rolling your eyes are other types of posture that might give you different levels of the same feeling.
By the same token, the more our figure was interested and/or affectionate towards the speaker, the more they might turn their body towards the speaker, incline their head towards them make eye contact with them, and give other clues with their posture as to their feelings and/or intent (example 6).
These are just tiny examples of how posture can illustrate what is happening within a static drawing and how a character might be feeling...here are some more examples of posture used to tell the story.
"Hellboy" by Mike Mignola
"Piracy" by Jack Davis (as a side note: I can't help but notice how well Jack Davis draws shoes, in particular the soles of shoes when they're seen from below. I always think of his drawings whenever I draw the bottom of shoes. But that's a whole other post to be written).
The other part of it, the "blood" part, isn't quite as important, but it is an interesting observation: all kinds of bodily fluids (as well as any other kind of fluid, or even solid for that matter) can be used to indicate movement within a static drawing (as well as to help tell the story). Just like posture, it can tell us what just happened, or what is happening right in the moment of the image.
The possibilities are limitless: if a character is smoking, the smoke from their cigarette could show us the path they traveled within the frame. If a character is bleeding, the trail of blood he leaves can show us the path he took. If a character just got punched, his flying teeth might add emphasis to the punch and show us the direction the punch came from. There are a million subtler ways to do this too.
Don't forget that clothes and hair can also help show us what direction the figure came from and how fast they are moving. Or, as in the example below, they can tell us how hard the wind is blowing and in what direction.
"The Spirit" by Will Eisner
In these two examples Alex Toth uses smoke to show us the movement of objects.
Here Carl Barks uses lines to tell us the path the whale has traveled, but you can see that even if there were no action lines, the direction and action of the water, ice floes, the pose of the whale and the indications on the ground where he landed would tell the same story clearly.
Anyway hope people find that worth reading about! I wish I had a dozen more examples but then I would never get this post up, and my collection of comics is far from exhaustive.