Body of Knowledge

ANIMATION GLOSSARY

Pixel Art Animation Glossary

A companion Article to our Web Animation Series

Introduction


After reading John Berry's excellent series on Animation within Websites, I decided to include our Animation Glossary.

It was originally published on another of our Websites that is dedicated to Pixel Art Animation: www.stixfigures101.com.

A

Animation
Animation is the process of creating a set or series of images that when displayed quickly, in sequence, give the illusion of movement.

See Flipbook and Illusion of Life, The.

Aspect Ratio
The ratio of an image or display device's width to its height, discribed as width:height.

Common aspect ratios are 4:3, used by old CRT Televisions and 16:9 for current flat panel displays.

A good, safe choice is 720p (1280 * 720 pixels). It is known as Standard HD and has an aspect ratio of 16:9.

See CRT.

B

Bitmap
A Bitmap or Bitmap Image is a Digital Image that uses a Matrix, or Grid of Pixels where each pixel may be any of a range of colors.

Technically, a Bitmap is an array of binary data that details the color values of a grid of Pixels that form a Digital Image!

Basically, it is a way of storing a square or rectangular Image, Digitally.

See Image and Raster for more information.

C

CRT
CRT stands for Cathode-Ray Tube. They were used in previous generation Televisions and Computer Monitors before flat-panel displays were invented.

See Aspect Ratio.

D

Dope Sheet
See Exposure Sheet.

E

Exposure Sheet
An Exposure Sheet or X-Sheet or Dope Sheet is a sheet or table, containing information about an Animation Sequence.

Originally Exposure Sheets were Camera Instruction sheets giving instructions to the Camera Operator on how to film the animation.

The instructions are written in a table with frames down the left-hand side and usually six columns across the page. The first column is a frame description and the remaining five columns: layers or depths of animation (imagine the frame being two-dimensional and depth as the third dimension).

Exposure Sheets are still used to describe Animation Sequences, especially when the sequence is complicated or has a lot of layers.

See Layer.

F

Fade
In Cinematography and Digital Animation, Fade is used to transition from one subject or scene to another. For example, from one location to another or from a point-in-time to another.

Some of the main types of Fades:
  • Fade-in
  • Fade-out
  • Cross dissolve
  • Wipe
  • Cut

See Wipe.

Field of View
In photography, Field of View or FOV is the part of the Universe that is visible through a Camera at a given time. Objects outside the FOV are not recorded by the camera.

In Digital Animation, FOV is the view presented by the Animator in the current Frame or sequence. As with photography, the Field of View can be changed by using Pan, Zoom and Fade.

See Frame, Pan, Zoom and Fade.

Flipbook
A flipbook or flip-book is a book or note-pad of sequential images that change slightly from image to image.

When viewed in-sequence, or flipped, the objects within the images appear to move or animate.

See Animation.

FOV
Field of View.

See Field of View for more information.

FPS
Frames per second or frames/second.

This indicates the rate of images, or number of animation frames per second.

See Frame Rate for more information.

Frame
Originally an animation Frame was a single still image on a Film Reel. When played by a Film Projector, at 24 frames/second, the series of stills, or Frames, gave the impression of movement. Hence the name Movies.

Digital animations and movies, use the same principle. A series of still Digitals Images (frames) are displayed in sequence, at a given frame rate (usually 30 frames/sec) to give the impression of movement.

You can also think of a Frame as a Picture/Photo Frame. The Digital Image is the photo and the frame represents the border or perimeter of the image. So, if you put the Digital Image in a smaller frame then you are effectively zooming-in. Putting it back in the original frame is zooming-out again.

See Animation, Image, Frame Rate and Zoom.

Frame Rate
The frame rate or frame-rate is the animation rate in frames per second or frames/second.

Originally animation used 24 frames per second. But computer animation generally uses 30 frames per second or even 60 frames per second.

If you're not sure what to use, 30 frames/second is a good, safe choice.

See Frame.

I

Illusion of Life, The
The Illusion of Life: Disney Animation by Disney animators Ollie Johnston and Frank Thomas was published in 1931. It introduced the 12 Principles of Animation based on the work of Disney Animators from the 1930's onwards.

The is book is generally referred to as the Bible of animation.

In 1999, The Illusion of Life was voted the number one "best animation book of all time" in an online poll by Animation World Network.

See Twelve Principles for more information.

Image
With respect to Digital Animation, a Digital Image is a drawing created by Image Editing Software and stored digitally as a file on a Digital Storage Device.

Digital Images are stored in many formats, such as BMP, GIF, JPEG or JPG, PICT, PNG and SCI to name a few. Each format has their advantages and some use compression to make the file size smaller.

As a Digital animator, the file types are less important than the Image being displayed accurately and that they are compatible with any Software you are using.

See Bitmap, Raster and Vector.

In betweens
In-betweens or Tweens are the images between Keyframes.

See Tween and Key Frame for more information.

K

Key Frame
Key frames or keyframes are key or important images in an animation. Generally the start-frame and end-frame of a short animation sequence.

In the manual or early-Disney days of animation, where images were drawn by hand, keyframes were drawn by the Master Animators and the in-betweens or tweens would be drawn by less experienced artists.

It is important to note that Keyframes are drawn first and dictate the content of all the in-betweens, drawn afterwards.

In the current age, where most animation is computerised, keyframes are drawn (using some form of image editing software) and the in-betweens may be drawn or generated by software.

See Tween for more information.

King Frame
A king frame or king-frame is a very important keyframe. Such as an important stage of an animation sequence that must be exaggerated or highlighted in some way.

Similar to keyframes, King-frames are drawn first, to set the scene for any related keyframes or tweens.

King-frames, by definition, must be drawn, or created, with a lot of care by a Master Animator.

See Key Frame.

L

Layer
Animation Frames may contain multiple layers to give them a 3D look.

This was an idea pioneered by Disney nearly 100 years ago. Walt Disney Studios invented the first Multiplane Camera to allow for seven layers of artwork, painted on glass, and filmed with a vertical, moveable camera.

Using multiple layers gives the impression of depth. An example of layering would be:
  • A background
  • Then a building
  • Some trees in front of the building
  • A character partly hiding behind a tree
  • And finally a character walking in the foreground

That's five layers, and should give a noticeable feeling of depth, particularly when you use realistic perspective.

See Perspective.

M

Multi-layer Images
Multi-layer images are used in Digital Art to give the impression of depth.

See Layer for more information.

O

On Two's
Animating on-two's means displaying each image for two frames. Animating on-ones would be displaying each image for one frame only.

For example, early Disney Animations were filmed on-twos. Even though they displayed the animation at 24 frames/sec, each drawing lasted for two frames. So only 12 drawings were displayed every second.

Computer animations can be on-ones, on-twos, on-threes or on-fours. Whatever suits the situation.

See Animation.

P

Palpable
A concept so obvious, that it can be easily seen or known; or a feeling so strong, that it can be touched or felt.

Also the PALPABLE Project: PIXL Animation Logical Projects And Basic Lexicon Engine.

Pan
To Pan is to move or rotate a camera from one position to another. For example from one side of a tennis court to the other.

Panning can also be used to follow a character as they move across the Field of View.

See Field of View.

Parallax
Parallax error or parallax distortion occurs where an object's length as viewed, is different to its real length or its apparent position is shifted.

It is caused by lines of site, e.g. where the eye is viewing an object at an angle.

It can also be caused by light passing through a prism, or medium, such as water or glass.

See Perspective.

Perspective
Perspective is the art of displaying three dimensional objects on two dimensional media, such as a page or a display device.

It involves adjusting the height, width and depth of objects and their position in relation to each other, to give the impression of three dimensions.

In simple terms, objects in the foreground should be larger than objects in the background and lines, such as roads and railway tracks, should converge or meet at a point in the distance.

See Layer.

Pixel Art
Pixel Art is Digital Art created by editing a matrix of pixels, or Bitmap, to form an Image. Think of Pointillism or Dot Paintings.

Classic Arcade games such as Space Invaders and Donkey Kong are effectively Pixel Art. If you use simple image editing software such as Paint or PaintPad, then you're creating Pixel Art.

See Pixel Art Animation.

Pixel Art Animation
Pixel Art Animation is created from Pixel Art Images. If you link a set of Pixel Art images into a sequence to form an animation, then you have Pixel Art Animation.

It's the most wholesome and true form of Animation in the Digital landscape. No Software Generated images, no Artificial Intelligence just hard work, sweat and millenium required!

See Pixel Art.

R

Raster Graphics
Raster Graphics uses Bitmap Images.

Bitmaps are a matrix or grid of pixels that may each be any of a range of colors. As such, Raster Graphics are two-dimensional and do not scale very well.

To create a 3D look with Raster Graphics, Layers and Perspective must be used but they will still not be as accurate as true 3D Images, created in three dimensions.

Pixel Art uses Raster Graphics and a range of Image Editing Software from simple to complex.

See Bitmap, Image and Raster versus Vector Graphics.

Raster versus Vector Graphics
Color Resolution and Complexity:
Raster Graphics are great to create detailed colorful images. Every Pixel may be a different color so they are perfect for storing photos and complex colorful graphics.

Whereas Vector Graphics generally have simple color-fills or gradients, so they cannot accurately reproduce colorful images or photos.

Image Creation/Editing:
Image Editing Software for Raster Graphics is extremely widespread. There are countless Apps for editing Bitmap images, some available for free and the rest generally cheap.

Although this is changing and may not be much of an issue, there is not as much Software available for editing Vector Graphics.

File corruptions:
Although this is rare, slight corruptions or loss of data in Raster Images will not overly affect their display.

However, slight errors in a Vector Image will be exagerated significantly.

File size:
Even with compression, Raster files can be quite large. Particulary when comparing them to the size of Vector files.

Vector Graphics files are quite small as they contain a lot less image data than Raster files.

Quality of Angled-lines and Curves:
Because Raster images are effectively made-up of square pixels, angled lines (not horizontal or vertical) and curves can appear blocky or ragged.

Angled lines and curves are much smoother in Vector images due to the way they are defined.

Scaling Images:
Because Raster images are made-up of a defined number of pixels (dependant on the resolution of the image), they do not scale well, especially when scaling-up (or zooming-in). Unless you have advanced image-correction software, zooming-in will always result in blocky distorted images.

Because Vector images are defined mathematcally, they can be scaled-up or down to almost any size with no loss of quality.

See Raster and Vector.

S

Static Tweens
Static Tweens are used where Animation doesn't change but additional Frames are required for timing.

For example, when creating a Graphic Novel, there may be a Speech-bubble displayed, so the animator must give time for it to be read, but there may not be any animation required. However, because you generally need 30 frames/second, a set of indentical Static Tweens will be required, to allow the reading time.

See Tween for more information.

T

Tween
Tweens or in-betweens are images between key frames. They may be manually drawn by an artist or generated by software in an Animation App.

An example of where tweens may be used is a character dropping a ball. The start-keyframe would be the dropping of the ball and the end-keyframe hitting the ground. The in-between frames, or tweens, would show the ball falling from the start to the end and could be created by an artist manually or by software automatically.

Tweens are also used where the animation doesn't change. For example, when creating a Graphic Novel, there may be a Speech-bubble displayed, so the animator must give time for it to be read but there may not be any animation required. However, because you generally need 30 frames/second, a set of indentical Static Tweens will be required, to allow the reading time.

See Key Frame for more information.

Tweening
The process of creating in-between images or Frames.

See Tween.

Twelve Principles
The Twelve Principles of Annimation were introduced by Disney animators Ollie Johnston and Frank Thomas in their 1981 book, The Illusion of Life: Disney Animation, based on the work of Disney Animators from the 1930's onwards.

Their main purpose was to produce an illusion that cartoon characters adhered to the basic laws of physics.

The 12 Principles of Animation:
  1. Squash and stretch
  2. Anticipation
  3. Staging
  4. Straight ahead and pose to pose
  5. Follow through and overlapping action
  6. Slow in and slow out
  7. Arc
  8. Secondary Action
  9. Timing
  10. Exaggeration
  11. Solid drawing
  12. Appeal

See Illusion of Life, The.

Two's
See On Two's.

V

Vector Graphics
Unlike Raster Graphics, Vector Graphics are not made up of a grid of colored pixels.

Rather, they are defined mathematically using Vector Paths that have properties such as color, thickness, shape and fill.

Vector Paths have direction and are defined in terms of points on a Cartesian (X, Y) plane, connected by lines and curves to form polygons and other geometric shapes.

Because Vector Graphics are defined mathmatically and not by pixels, they can be scaled up and down, accurately, without any loss in defintion.

See Raster versus Vector Graphics.

W

Wipe
Wipe is a type of Fade or Transation that replaces one Shot or Scene with another by travelling from one side of a frame to the other (similar to a car wind-screen wiper).

See Fade.

X

X-Sheet
See Exposure Sheet.

Z

Zoom
To Zoom or Zooming in both Photography and Digital Art means to make your Subject smaller or larger in the Frame without changing your position.

Zooming also changes the Field of View, making it smaller or larger. So you see less or more of the landscape around the Subject.

In Digital Art, Zooming-in is achieved by making the Subject larger and trimming-off the edges of the image to fit the Frame.

While Zooming-out requires adding Artwork to the edges of the image. As the Subject is smaller and the original image no longer fills the Frame.

See Field of View and Frame.
Tim StiX - Nov 2020
Tim StiX is a Software Engineer with over 20 years experience in Net Technology.
See timstix.com for more information.
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