Whenever you save something, whether it be a document, an image, some music, you will without acknowledging it most of the time be using a form of file type. They come with different names and different roles for a reason and fortunately most of the work is done for us so we merely have to just click save. This report will go through some of the more well known, as well as the ones you may not have heard of.
The Portable Document Format, which is what PDF stands for, is defined as “a file format for capturing and sending electronic documents in exactly the intended format”. Originally thought up in 1991 by Adobe co-founder John Warnock as Camelot, it eventually evolved to be known as PDF and was released to the public in 1993.
PDF combines 3 technologies:
- A subset of the PostScript page description programming language, for generating the layout and graphi
- A font embedding/replacement system to allow fonts to travel with documents.
- A structured storage system to bundle these elements and any associated content into a single file, with data compression where appropriate.
Adobe patented PDFs but use a royalty free patent meaning anybody can create one for free.
A number of different programs use PDF for a number of jobs:
Programs such as Adobe Illustrator, Adobe Acrobat and OpenOffice allow people to create files and then export them as PDFs.
Programs such as Adobe Reader and plug ins within Mozilla Firefox allow people to view PDF files.
PDF files so commonly used for a number of reasons such as:
- They are quickly and easily created.
- They can be secure as the creator can password protect, watermark or encrypt files they don’t want people to see.
- They are compact and are able to compress large files.
- They are self contained.
The Photoshop Document is a proprietary file and is mainly used in Adobe Photoshop, Photoshop Elements as well as Corel Paintshop Pro.
It is a layered image file so it allows you to open the image you are working on and be able to access the individual layers after saving. JPEGs are flattened images so do not let you do this.
You can also view PSDs using Apple Quicktime Picture Viewer but you cannot edit the image.
The Joint Photographic Experts Group file type is probably the most well known and encountered out of the ones looked at.
It is used most, if not all, image programs as well as being the most commonly encounter method of storing and posting images on the internet.
“The JPEG standard specifies the codec, which defines how an image is compressed into bytes and then back into image.”
JPEGs use a lossy compression which means the image loses quality as it gets smaller.
They are used so much because they can contain many continuous colours, 16.7 million of them in fact, and the quality of the file is also adjustable.
Created in 1986 by a committee chaired by Aldus Corporation, who are now a part of Adobe, the Tagged Image File Format was an attempt to standardise the type of image file formats companies use.
It can be opened using Photoshop, as well as other built in photo viewer programs.
It is used in desktop publishing, 3D applications, faxing and medical image applications.
One reason is it used is because it doesn’t use compression meaning there is no loss of image detail, which shows it’s importance for medical and faxing.
However the lack of compression is also a weakness because it means that files will take up more space than a JPEG will.
Portable Network Graphics are a file format image compression which is tipped to replace the GIF file.
It is the most used lossless image compression format on the internet.
They are popular because, unlike the GIF, they were created by an internet committee to ensure that there was a patent free alternative.
It can also be compressed up to 10-30% more than a GIF, and it’s interlacing is supported and faster in developing. However, it doesn’t support animation.