Digital Graphics File Formats

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Raster Graphics

Raster graphics are images that are made up of square pixels which are in a fixed resolution meaning they cannot be enlarged without a significant loss of quality occurring, as seen here:

Vector Graphics

Vector graphics are images that are made up of lines and paths that have a start and end with points between the start and end. Vectors have the computer create the points when the image is altered so quality is not lost during resizing. As seen below.

Raster Graphics

JPEGStands For Joint Photographic Experts Group

Used For/Example JPEG’s were made to be the universal file format that all computers could read and are primarily used on the internet due to their small size.

Advantage -Small size so easily downloaded online-Recognised by almost every device-Easy to upload for everyone due to small size.

Disadvantage -Loses quality ever so slightly when opened, this means after multiple opens the image will be far worse than the original-Hard to edit due to fixed resolution

TIFFStands For Tagged Image File Format

Used For/Example Used for desktop publishing in magazines, book etc. InDesign exports TIFF files.

Advantage -Saves multiple pages into one file to help with organisation-No quality loss through compression

Disadvantage -Due to amount of pages and content this results in huge file sizes.-Not as universal as the JPEG-Takes a long time to download due to file size.

GIFStands For Graphics Interchange Format

Used For/Example Short digital animations. Used mainly online

Advantage -Takes less time to load than a video in most cases.-More visually appealing than a still image.-Beneficial to people with slow connection as GIF’s can be used as an alternative to video.

Disadvantage -Larger file sizes as appose to just displaying still images-If incorrectly done the finished product can be very jittery.

BMPStands For Bitmap Image File

Used For/Example Bitmaps tend to be used by cameras because of their small sizes.

Advantage -Easily created meaning it is possible with portable cameras.-Mostly produced in image capture devices meaning they are the universal file type for cameras

Disadvantage -Raster graphic, so zooming and enlarging results in quality loss.-The higher the quality of the image the higher the file size will be

Vector Graphics

PSDStands For Photoshop Document

Used For/Example Saving work done in Adobe Photoshop such as image alteration.

Advantage -Saves all layers into one file-Supports transparency-Fast and easy image alteration

Disadvantage -Only accessible by Photoshop-File sizes can become huge depending on amount of layers added.

AIStands For Adobe Illustrator

Used For/Example Used for Adobe Illustrator for projects such as digital art and logos.

Advantage -Works on vectors meaning alteration can be done with ease -Similar to Photoshop with quick image alteration.

Disadvantage -Only accessible via Adobe Illustrator -Not as approachable as other software more orientated towards experienced editers

FLAStands For Flash File

Used For/Example Used for making animations and in some cases games, mainly online

Advantage -Can include sound and or video-High quality files with low file sizes-Widely used across the web-Flash is constantly being updated

Disadvantage -Can in some cases cause websites to take slightly longer to load-May become tedious after many uses -Flash required to view files

WMFStands For Windows Metafile

Used For/Example Originally intended to be a universal format (like the JPEG) but never took off

Advantage -Mix of both vector and raster graphics.-Can be scaled with no loss of quality -Compatible with most if not all Microsoft based software

Disadvantage -Out-dated and mostly seen as amateur/unprofessional (made in the 1990s) -Not compatible outside Microsoft software

File Format Capture and Optimising

CompressionDefinition Compression is when file sizes are

reduced by minimizing the amount of image information saved in the file:Lossy Compression – Where image info is lost in the process Lossless Compression – No image info is lost

Advantage Helps with uploading a picture online or when space required on a memory unit is needed as files sizes are reduced.

Disadvantage When most images are compressed the more the quality will degrade such as GIF’s, PNG’s etc.With a JPEG image information will be lost permanently meaning when passing the file on the image quality will be gone

Image CaptureMethod Scanner

How is it used for image capture of graphics

An item is placed on the scanner, then the light bar runs across the item which illuminates it meaning it is reflected into two or three mirrors then reflected into the lens.

Method Camera

How is it used for image capture of graphics

The camera is first pointed at an item or person then the lens focuses the light either automatically or manually, then the user presses the capture button making the shutter open then close quickly letting the light (image) through.

Method Graphics Tablet

How is it used for image capture of graphics

The user has a stylus to “draw” an image on the tablet, some tablets have different pressure sensitivity. The image can then be transferred by USB or sometimes Bluetooth to a computer

OptimisingWhy would you optimise? To make an image more accessible to

people who want to see it eg. On a website or via e-mail

How can you optimise? Pixel amounts of an image can be changedto make a file larger or smallerBit depth can also be altered, lower bit depth results in less colour and higher bit depth means more colour.

Advantage to optimising Optimisation can make an image ideal for the scenario for instance: if a file is too small or large for upload by changing the pixel amount it can be made just right.

Disadvantage to optimising If bit depth is lowered too much it will cause the image to have no colour and if the bit depth is increased too much it will cause the image to look oversaturated.