Digital Graphics File Formats

Jess Stanton

Raster Graphics

• Most images used on a computer are raster graphics such as ones found on the internet and pictures imported from cameras. They are made up of a grid of pixels which are usually known as bitmap. The larger the image the more space it will take up due to raster graphics needing to store so much information the large bitmaps require large file sizes. However there are compression formats that reduce file sizes such as JPEG and GIFs.

Vector Graphics

• Vector graphics are made up of vectors, more commonly known as paths and strokes. They have a specific start and end point with curves and angles in between which make them more flexible and can become and line, a square, a triangle or a curvy shape. When they are resized there isn’t much pixilation due to the ratio of the parts to other parts being changed not stretched. They are useful for businesses cards or big billboards as they have no loss in definition when changed.

Raster Graphics

JPEGStands For Joint Photographic Experts Group

Used For/Example • Photographic and Web formats

Advantage • JPEGs are universal – every device that shows pictures uses / shows them in the JPEG format

• Made up of thousands or millions of colours

• Small file sizeDisadvantage • Low quality

• They loose quality due to the compression and recompression each time they are edited and downloaded.

TIFFStands For • Tagged Image File Format

Used For/Example • Desktop publishing• Used popularly by graphic designers

Advantage • Have the option of lossless compression which doesn’t effect loss in quality.

• Adobe InDesign documents saved as TIFFs and can save multi page documents to a single TIFF file

Disadvantage • Large files sizes due to no compression • Wont open in as many devices• More specialist software involved so

can be complex to use

GIFStands For • Graphic Interchange Format

Used For/Example • Short digital animations often on the internet

Advantage • They are small files sizes and they can be used easily online as the can load quicker

• Can be of anything so appeal to anyone

Disadvantage • Poor quality• Can have a lack of quality due to only

having a maximum palette of 256 colours

BMPStands For • Bitmap Image File

Used For/Example • Digital Image

Advantage • Can be sent to people and they can still open them

• Quality stays up due to no loss when compressed

Disadvantage • Does not support compression, which means very large files

• BMP files are not supported by Web browsers

Vector Graphics

AIStands For • Adobe Illustrator

Used For/Example • Logo creation• Graphics to represent a company

Advantage • Can be scaled to big or small as vector graphics have no loss in definition

• When image is zoomed in on, unlike Photoshop the quality stays the same

Disadvantage • Big file sizes• Can only be opened if the device has AI• Complicated to learn how to use at first

FLAStands For • Flash file

Used For/Example • Creation of animation and games

Advantage • Can produce high quality files with a small file size

• Can include sound and videos• Can be used easily and watched easily

online

Disadvantage • Text has to be shortened as content capacity is limited

• Flash files are hard to update• Flash files don’t work on certain phones

and tablets which are highly popular

WMFStands For • Windows Metafile

Used For/Example • Microsoft Clipart• Used for logo creation

Advantage • Similar to AI files• Are often copyright free• Can contain both vector and bitmap

components • Can be big or small as vectors have no

loss in definitionDisadvantage • They can only display 256 colours

unlike, say a JPEG which have 16 bit colour

• Security issues have been reported where by a computer code can be embedded in them

File Format Capture and Optimising

CompressionDefinition • The action of reducing a file size.

“When a file or a group of files is compressed, the resulting ‘archive’ often takes up 50% to 90% less disk space than the original file” http://www.techterms.com/definition/file_compression

Advantage • Makes files smaller, which can make them easier and quicker to download over a network or the internet

Disadvantage • Images become pixelated as they are compressed as they save smaller amounts of coloured squares each time

Image CaptureMethod Scanner

How is it used for image capture of graphics

You can digitise physical images like sketches, physical photos or mixed media products

Method CameraHow is it used for image capture of

graphicsTake a picture of the graphic (this will turn a vector image onto a bitmap)

Method Graphics TabletHow is it used for image capture of

graphicsLets you control the mouse like a pen allowing enhanced control of drawing or selection.

OptimisingWhy would you optimise? Files that aren't optimised have a larger

file size making downloads longer

How can you optimise? • You can optimise for web by reducing the “Image size” in Photoshop

• Reducing resolution• Reducing bit depth

Advantage to optimising • Images uploaded to the internet are optimised to ensure easy viewing on the web.

Disadvantage to optimising • Images should only be up to 500 pixels otherwise quality is lost.