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 or a grid of pixels which are usually known as bitmap. The larger the image is the more space it will take up and due to raster graphics needing to store so much information the large bitmaps require large file sizes. However there are compression formats that reduce files 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 a 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 business 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 size

Disadvantage • 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 losslesscompression which doesn’t loose quality.

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

Disadvantage • Large file 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 file sizes and they can be used easily online as they can load quicker

• Can be of anything and so appel to anyone

Disadvantage • Can have a lack of quality due to only having a maximum palette of 256 colours

• Poor quality

BMPStands For Bitmap Image File

Used For/Example • Digital Image

Advantage • Can be sent to people and they can stillopen 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

PSDStands For Photoshop Document

Used For/Example • Image Manipulation e.g. front covers of magazines

Advantage • Can use text in this program• Support transparency and so can

improve overall appearance of areas such as websites

• Saves layers, page formatting information, swatches etc..

Disadvantage • Doesn’t have spell check and so means you have to check through work to make sure it is faultless

• Can only see image if device has Photoshop program too

• Big files sizes if there is lots of information e.g. lots of layers

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 it

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 definition

Disadvantage • They can only display 256 colours unlike, say a JPEG which have 16 bit colour

• Security issues have been reported where by 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 thee internet

Disadvantage • Images become pixelated as they are compressed as they save smaller amounts or 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 Camera

How is it used for image capture of graphics

Take a picture of the graphic (this will turn a vector image into a bitmap)

Method Graphics Tablet

How is it used for image capture of graphics

Allows you to control the mouse like a pen allowing for enhanced control of drawing or selection

OptimisingWhy would you optimise? Files that aren’t optimised have larger file

sizes making downloads longer

How can you optimise? • You can optimise for web by reducingthe “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 500 pixels otherwise quality is lost