Differences between file types

Here is a small introduction to the different file extension, what a file extension is, how to recognise different file extension, the differences between them!

Here is a small list of various extensions:

• PSD
• JPG
• Tiff
• PNG
• Gif

A file extension is a way of labelling the names of files so you and your computer can know what they contain and what type of program created the file and what program to use to open it.

PSD: A .psd extension is a layered image file used in Adobe Photoshop. It stands for Photoshop Document and it is the primary document save file in the program. It allows users to interact with the images layers after it has been saved. If it is saved as a different document however it cannot be converted back to a .psd for the user to work with the individual layers.

JPG: A .jpg extension is a standardised image compression mechanism which allows the user to save a large image to about 5% of the images actual memory size but at the price of loosing some clarity/information. It works well with photographs, naturalistic artwork and similiar material but not as well on lettering, simple cartoons or black-and-white line drawing. However all file extensions for images loose some information, a .jpg retains a considerable amount more than a .gif but doesn't support motion (however an .mpeg would).

Tiff: The .tiff extenssion is a bitmap graphic file format, it was developed in 1987. It is an old format that makes it possible to store large file types losing quality despite the platforms or peripherals used. It also allows images to be stored in black and white, true colours as well as indexed images, using a 'palette'.

PNG: The png. extension was created by a group of people after the .gif format was patented making people have to pay a license fee for its use. It is superior to the .gif as it supports millions of colours and better file compression. It doesn't support animation but an .mng extension does.

GIF: The .gif extension was created in 1987 by request of Compuserve who wanted a platform independant image format that was able for transfer across slow connection. It is an 8 bit format which means it can only hold 256 colours due to the format. There are two standards labelled 87a and 89a (after the year each was created). The 89a format allows for greater interlacing, to define one colour to be transparent and the ability to store multiple images in one file to created a basic form of animation.