2D Game Animation Frame to Frame shading and Coloring Variations?

I'm not good at pixelling or other 2d art myself, but here is some advice.

Remember that except for real life, anything digital that you see is already frame by frame, including movies, 3d games, etc... Of course the actual framerate varies, but the same rule applies. So, take a look at something similar to what you want. If you are interested in low-rez pixel art, take a look at similar games like old mario, zelda, final fantasy, etc... You could go even older to Atari style but there isn't any shading in those sprites really due to hardware limitations. But NES, SNES, Commodore 64, among others are great examples as they started having shading by then. The same rules apply if you want to do different styles, including higher resolution pixel art, brush art(or whatever you call it), vector art, whatever.

So, remembering the rule above about things working frame by frame, note that your eyes work out the in-betweens most of the time as long as you have enough frames. Pixel art generally got away with only 4 - 8 frames for a walk cycle, and it was enough, and did not look bad. Higher resolution art requires more frames for things though, as there is simply more information for the eyes to process and it gets jerky to the viewer without more frames.

So, just draw the frames and adjust the lighting to be from the same direction. Our eyes will work it out, especially if it is low-rez pixel art. Just remember in general what is light and what is dark. If my character is a kangaroo, and my lighting is from the upper right, the stomach of the kangaroo will by light nuetral to dark, as it is facing away from the light but isn't exactly in shadow either. But if I have an animation where he/she leans back on the tail(to kick the feet up), then that same stomach area will now be facing the light and need to be brighter shade of the same color in the palette, while the head will be more in shadow depending on how far back the head goes.

Though I mostly talk about pixel art, the above applies to all types of art, even 3d though it is usually automatic from lighting in the engine. If you do vector art, you will have shapes and gradients for lighting(depending on the style you choose), so you would possible move those around some too, unless you want the lighting to not adjust on your objects as animation happens. Some games do that, but I don't like it that much.

How do you keep the frames consitently colored or shaded if you draw them one by one?

You don't draw them one by one. Since the consistency between each frame is paramount, you work in stages.
An example would be first doing a structural pass (drawing the skeleton of the character for all frames), then a volume pass and then finalising with a colouring pass. You only get to the next pass after the current one is satisfying.
You'll make extensive use of onion-skinning \ light-tableing as well (sketching on top of a semitransparent version of the previous frame). The more experient you are, the faster you'll work. In the future you'll only do a volume \ outline pass and colouring pass, without the need for an early skeleton pass - something that you were only doing when you were starting out.

In each pass you'll be constantly 'flipping' back and fourth between the current and previous frame to test for temporal coherency and fluidity. This is something you'll pick up better when you start practising.

This is something that I've written some time ago, but know that I'm no authority on the subject: http://www.gamedev.net/topic/658693-does-anyone-have-time-to-maybe-edit-this-design-of-my-player/#entry5166925

Do you use raster programs? Vector programs? Or do you use a combination like sketch in vector and paint in raster or vise versa?

It mostly depends on what your software offers. Most animation software only works with vector graphics because they require less memory, are dynamic (can be deformed etc.) and are resolution independent (a vector animation from years ago can be rendered again for Blu ray mastering, for example).

I think animation software is a bit elitist right now. Anything that is good costs a lot, there isn't free software in the likes of Inkscape, GIMP or Blender that's focused on 2D animation production.
You could say that Synfig is that program, but it is extremely buggy - in the same notebook I manage to run and work with 3ds max 9 or Toon Boom Studio or Photoshop, while Synfig crashes consistently. What's the excuse?

If you want a minimalistic software to play with 2D animation, give Pencil2D (free / open-source) a try. It's good for practising.
If you're talking about low resolution animation (as in, pixel at animation for platform games, J-RPGs etc.), there's Graphics Gale and ProMotion (both commercial).

Thanks guys for the tips.

Looks like there's no magical software or set method for this kind of stuff.

This forum is better than others, I got replies and tips!

This is something that I've written some time ago, but know that I'm no authority on the subject: http://www.gamedev.net/topic/658693-does-anyone-have-time-to-maybe-edit-this-design-of-my-player/#entry5166925

That's a very nice article!

Are there other articles/tutorials regarding this subject or is this topic rarely discussed? I mean the mythodology of creating frames/animation.

The exceptionally talented people -- those that you want to hear from the most -- usually keep their personal methods to themselves. But you can learn the standard approach in most literature on "animation production" -- storyboard, animatic, keyframes, clean-up etc. These are usually about broadcast or feature-film animation, so you'll have to adapt what you learn to producing animation for games.

You need to scavenge for material anywhere you can, if you don't plan go the formal route of enrolling in a CalArts animation course.

Here are some suggestions:

- http://www.newgrounds.com/bbs/forum/17
- http://www.conceptart.org/forums/forumdisplay.php/239-ANIMATION
- http://www.amazon.com/Animators-Survival-Kit-Principles-Classical/dp/086547897X/ (or just searching for books on "Animation" will give you plenty of results.)
- http://www.theanimatorssurvivalkit.com/ (It seems there's a DVD set with video lessons now, but it's very expensive.)
- Spazkid Flash tutorial (I found this out of a quick read through that Newgrounds link, so you can potentially find much more.)
- Artist blogs and enthusiast websites such as: http://onanimation.com/2011/06/27/ariel-pencil-test/ and http://onanimation.com/2011/05/24/ken-duncan-pencil-tests/

EDIT: No amount of theory study will help you move forward if you don't get a pencil and paper and start drawing.
This is a trait that you can find in all talented animators: they all draw well.
If you pratice with traditional media (pencil, pen etc.) you can easily transfer your skill to the digital realm (with a graphics tablet and decent software), so it's especially interesting if you can turn off the computer in order to practice sketching frames.

If you are having difficulty with shading and pose (as I do on the rare occasions when I try to hand-draw stuff) one trick you can do is to do a very rough block-out of the character and pose in something like Blender then set up your lighting the way you need it and do a render of the mock-up to use for a paintover. By using a properly lit render, you have a better idea of how the light falls on the shape and of how the limbs and appendages of the character lie at a given pose.

No amount of theory study will help you move forward if you don't get a pencil and paper and start drawing.
This is a trait that you can find in all talented animators: they all draw well.

Yeah well, I don't plan to enroll in a course, I have read that it is not a requirement. I do draw as a hobbyist, but never had formal education, I just love doodling.

Thanks a lot for links, I like these forums