Glossary of terms

Audio level compression is not to be confused with audio data compression.

Compression is the process of lessening the dynamic range between the loudest and quietest parts of an audio signal.

Most sound for television and film is compressed.

Cyan, Magenta, Yellow and Black. CMYK is a subtractive colour model, used in colours printing, and is also used to describe the printing process itself.

The CMYK model works by partially or entirely masking colours on a lighter, usually white, background. Such a model is called subtractive because inks "subtract" the colours red, green and blue from white light.

Also known as a "network protocol". A system of rules that allow two or more systems to transmit information.

Popular communication protocols on the Internet include, HTTP/HTTPS, FTP, SMTP DNS and TELNET.

When you refer to the height and width of an image, you're talking about its dimensions.

For example, if an image is 500 pixels wide and 200 pixels high, you could say that its dimensions are 500px by 200px (the width is usually listed first).

A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images.

Every type of modern technology uses dot matrices for display of information, including mobile phones, televisions, and printers.

Dots per inch. A measure of spatial printing, video or image scanner dot density.

An adjustable feature in editing software when a caption is keyed onto a background. A drop shadow border (usually dark) helps the caption (usually light) stand out on bright or busy backgrounds.

The shadow can be made to "drop" in any direction (even up!) and can have different width borders. 

A file format is the structure of how information is stored in a computer file. A program that uses the data in a file must be able to recognise and access data within the file.

For example a Microsoft Excel file (.xlsx) will not be able to be opened in Microsoft Word as it is not saved as a .docx file.

The file formats are often indicated as part of a file’s name by the file name extension on Windows-based computers.

Graphical Interchange Format. Pronounced JIF or GHIF, GIFs are a small compressed file used for web animation, they contain the timing information and animation frames.

 GIF images support transparency.

Hypertext Markup Language. Lets authors tag or "mark up" their content in order to control how the content is displayed in a web browser.

With HTML, authors can define the structure of a webpage, and add other elements such as hyperlinks, images and buttons.

An interlaced picture has each frame divided into two fields.

Interlacing reduces the perception of screen flicker but can cause annoying interference effects with images such as computer generated text and graphics when used in a TV environment. 

Joint Photographic Experts Group. Pronounced "jay-peg", this file type is commonly used for photographs, and most digital cameras save photos in this format by default.

JPEG images do not support transparency.

JPEG uses lossy compression, which means it provides a reasonably high level of quality without a very large file size. 

Moving Picture Experts Group. A digital compression standard for moving video images that allows the images to occupy less memory or disk space.

Like the JPEG standard, it includes options for trading off between storage space and image quality. MPEG videos include metadata expressing creation details and other properties.

A compressed coding format for digital audio.

A digital multimedia container format most commonly used to store video and audio, but it can also be used to store other data such as subtitles and still images.

Opacity is the degree to which a video image is transparent thereby allowing images that are layered behind to visually show through.

Audio

Panning is where a sound source is moved within a stereo image – left to right or vice versa. The panned sound is usually a single source of sound such as a solo voice or instrument.

Video

A pan is where a camera is moved in a mainly horizontal plane in either direction.

Portable Document Format. Developed by Adobe to present documents, including text formatting, images and other digital objects.

The main benefit of PDF documents is consistency across multiple devices and platforms.

A single picture element, or the smallest element in a graphic image.

Picture quality increases as the number of pixels that are used in a measured area of an image, just like dots per inch (DPI) in the printing world.

Portable Network Graphics. Pronounced "ping" or "p-n-g", this file type is commonly used for graphics and illustrations, although it can also be used for photographs.

PNG images support transparency.

PNG uses lossless compression, meaning photographs saved with this format will usually be of a higher quality than JPEG images, but the file size will be much larger. 

Pixels per inch. These are measurements of the pixel density (resolution) of an electronic image device such as a television of computer monitor.

Images made up of a rectangular grid of pixels.

Popular raster graphics editors include Adobe Photoshop, GIMP, MS Paint, Paintshop Pro, Painter and Paint.NET.

Also known as image synthesis, rendering is the automatic process of generating a photorealistic or non-photorealistic image from a 2D or 3D model.

Image resolution is the detail an image holds. The higher the resolution, the more detail it will have.

Second Level Domain. A second-level domain is a specific part of a website address that complements a top-level domain.

For example, in example.com, example is the second-level domain of the .com TLD.

Tagged Image File Format. TIFFs are an extremely high quality, loseless file type ideal for photography and printing. They often produce large file sizes.

TIFF images support transparency.

A graphical representation of the edits of a video, from start to finish.Individual tracks are displayed along with a timecode timescale ruler.

Separate media chunks are moveable within the timeline to suit the creative process of joining shots together into sequences.

Top-level domain. Refers to the last segment of a domain name, or the part that follows immediately after the "dot" symbol.

Examples of some of the popular TLDs include .com, .org, .net, .gov, .biz and .edu.

Images made up of paths that have a start and an end and include points and curves.

Popular vector graphics editors include Adobe Illustrator, Inkscape, CorelDraw and LibreOffice Draw.

Also known as magnification. To zoom is to enlarge or reduce the apparent size of an image, not it's physical size. Within applications, zoom is often expressed as a magnifying glass symbol.