Digital Graphics File Formats

Lauren Pyne

Raster Graphics

Raster graphics are images made up of bitmaps.

Bitmaps are small pixels made up of colour, each pixel records the colour information for that part

of the image. These images have a fixed resolution and have a trouble resizing as it distorts the

image because the pixels are stretched and become more visible.

Megapixels relates to the millions of pixels that the image is separated into, for instance, a 14

megapixel image will have 14,000,000 pixels.

Bitmaps separate the image into (i.e.) 14,000,000 pixels, each one of these pixels records the

colour information, all these different colour variations create an image. When enlarged these

pixels get larger and become more and more visible. The more visible the pixels, the more

pixelated and distorted the image looks.

These graphics can be seen in JPEG images, GIF’s and PNG files.

Also, modern display screens have raster graphic displays.

Vector Graphics

Vector graphics are made up from vectors, or also known as paths and strokes. They are defined

by a start and end point, with curves, points and angles in between the start and end point. From

this, the path can become a line, square, triangle or curvy shape. Each path may be given a

stroke colour, shape, thickness, and fill.

Vector graphics are better quality and easier to resize. They can be resized from the label on the

bottle of a drink to the size of the logo on the side of a truck. Resizing changes the difference of

the pixels. These graphics are used for company logos because they are much easier to resize

and don’t lose definition or get distorted when being resized.

Raster Graphics

JPEGStands For Joint Photographic Experts Group

Used For/Example Photographs and web formats.

Advantage The JPEG file format is universal. The images can also be saved as low quality to help with quick downloading and saving.

Disadvantage JPEG files lose quality when edited multiple times due to the compression and recompression of the image. This is because each time it is compressed it loses information and the image lowers in quality because of the loss in information.

TIFFStands For Tagged Image File Format

Used For/Example TIFF file formats are used in graphic design.

Advantage TIFF files allow the user to have multi page documents all on one file. This is an advantage for those who create magazines. These files are also high quality. These files dont lose quality due to compression.

Disadvantage It wont open on as many devices or software. The software used creates a limited access and requires a knowledge on the software to use it. These files are also too large to send via email, so another file sharing website must be used if you wish to send them online. The high quality files also take longer to download.

GIFStands For Graphics Interchange Format

Used For/Example Short digital animations usually on the internet

Advantage Small file type, looks like a low quality video in a loop. They are a series of JPEG images that look like a video. GIF’s also support transparent backgrounds.

Disadvantage These files are poor quality and are short, they rarely exceed 10 second loops. They only have a maximum colour range of about 260 colours so they can sometimes look poor in quality, leading to the images having more blocky colours and looking pixelated.

BMPStands For Bitmap image file

Used For/Example Used to store bitmap digital images

Advantage These files can display a picture realistically. This file is similar to a TIFF and JPEG file, it is also used in the programme paint. This file is universal and has no loss of information through compression.

Disadvantage Although this file may be universal, its outdated. It has large file sizes, this makes it difficult to send, download and save.

Vector Graphics

PSDStands For Photoshop Document

Used For/Example Image manipulation, and post production for raster graphics.Used for the front cover of magazinesUsefull among photographers and graphic designers.

Advantage This file format supports layers, formatting information, swatches, in case upon reopening of the file adjustments to layers etc must be made. Supports transparency. Has a text tool.

Disadvantage The disadvantage to a PSD file is that you need Photoshop to open the image, the file format is not universal, and you need to know how to use, and understand photoshop.

AIStands For Adobe Illustrator Art

Used For/Example Logo creation

Advantage These images can be scaled large or small, as vectors have no loss of definition.

Disadvantage This programme is complicated to learn how to use, using large file types that can only be opened in Adobe Illustrator. They must be saved as a different file type if you wish to show someone who cannot access Adobe Illustrator.

FLAStands For Flash File

Used For/Example Used to create animations and games.

Advantage They can create high quality files with a small file size. These files can include sound and video and are good to use on the internet due to the small file size. It is also possible to create a website using Flash

Disadvantage This file type is not fully universal, and if you were to create a website using flash, it may need high internet speeds to load. Flash also requires the users computer to have Flash player installed, although most computers its already installed. Flash files must be converted into a different format before they can be used on the internet

WMFStands For Windows Metafile

Used For/Example Used for logos and clip art.

Advantage These images are similar to AI files can be scaled large and still have no loss of definition. These files can contain both vector and bitmap parts.

Disadvantage Not universal, and seen as JPEG is universal, in most cases WMF is unnecessary.

File Format Capture and Optimising

CompressionDefinition Lossy compression is how the sizes of file

types is reduced. They are reduced by reducing the amount of information that is stored in the file.

Advantage The files are smaller, easier to send, receive and download. This also allows for more data to be stored on the computer.

Disadvantage Images can become pixelated becausethey are compressed and less amounts of information are saved. This means that less of the coloured squares are saved each time, creating larger blocks of colour.

Image CaptureMethod Scanner

How is it used for image capture of graphics

This allows you to make physical images such as sketches, physical photographs, collages into a digital images.

Method Camera

How is it used for image capture of graphics

A photograph can be used to digitalise the media products, but not in as good quality, this however allows you to take images of a 3d subject

Method Graphics Tablet

How is it used for image capture of graphics

These can be used to control the mouse like a pen, for controlled digital drawings-good for drawing cartoons, selection and digital handwriting.

OptimisingWhy would you optimise? You would optimise an image that would be

uploaded to the internet to ensure that it is easier to view on the web. Non optimised images have large file sizes and take longer to view or download

How can you optimise? You can optimise images by changing the images size in Photoshop to less than 500 pixels wide. You can optimise an image by reducing the image size, the bit depth and image resolution.

Advantage to optimising It speeds up the web pages performance, while the image size has decreased, the image quality is reasonably maintained.

Disadvantage to optimising Image information is lost to make the file size smaller. These images will struggle to be resized properly as they have adjusted the file to say that the image is less than 500 pixels wide.