City and Islington work: Digital Graphics for Print unit 54

Task 1: write about file formats

In a computer, there are different types of files. Each computer device holds files of data that are typically used by individual applications in the computer. A file format gives a description on how a file will be encoded for storage in the computer. All files needs to be encoded before they can be saved into a file. On the computer there are some programmes that have a rage file formats that could be saved in a different file format from the format you would using to create that file. This is an example of how you could save in a different file format.

As for some file formats are not interchangeable between software. Each software vendor creates a file format for its specific software application. This makes sharing files between software’s extremely difficult, so you do not have the chance of saving the file to a different file format.

File Formats:

PNG files can do a good job on showing both line graphics and bit-mapped graphics. Most web browsers support the PNG format, which makes it easy to include pictures directly in a web page. What the PNG has is binary, colour 24 bit, its 2D and it uses loss less compression. What lossless compression is, with every single bit of data that was originally in the file remains after the file is uncompressed. All of the information is completely restored. This is generally the technique of choice for text or spread sheet files, where losing words or financial data could pose a problem. So the reason why PNG format is used because it allows images to be saved with transparent backgrounds and PNG is created to use online and not for print. As GIF and PNG are similar formats , its hard to know which one is better then the other but what PNG format has that GIF does not , is PNG has a much higher colour depth then GIF so PNG looks more real with colours shown in the image.

The TIFF (Tagged Image File Format) file format is different; it allows a flexible set of information fields. TIFF supports files with 24-bit (16.7 million) colours. You can even save up to 48-bits of colour information within the file.The clear benefit of this scheme is that almost any information can accompany an image, while little information is absolutely needed, and image headers remain as lean as possible. TIFF defines support for multiple images in a single file. TIFF also preserves layers when saved from Photoshop. So when is TIFF used and why? TIFF is used when you do not want to lose the quality in an image and do not mind having a large file size. The file is large because it has all the information on the photo and it uses lossless compression, which because of these the file ends up big. TIFF is used to print because less colour and tonal information is lost through this form of image storage. So what is the down side of TIFF? Well it’s the file size. Depending on the bit depth (24 or 48) it will take 100MB for a single file.

JPEG (Joint Photographic Experts Group) is the right format for photo images, which must be very small files, for example, for web sites or for email. JPG is often used on digital camera memory cards. The JPEG format can compress images that contain up to 16.7 million colours. So what does JPEG have? It has is binary, colours ( 24 bit, which 8 bits each are of RGB, its 2D, lossy compression and only has Image. As it uses lossy compression, it reduces the size of an image by discarding details that are not much clear to the human eye. So what is lossy compression? What Lossy compression does, it reduces a file by permanently eliminating certain information, especially redundant information. When the file is uncompressed, only a part of the original information is still there (although the user may not notice it). Lossy compression is generally used for video and sound, where a certain amount of information loss will not be detected by most users. JPEG analyzes what date is the most important and cuts off the bits that are not much needed in the image. So what id the down side of JPEG? Well as JPEG uses lossy, each time you save a JPEG image, more date you will lose.

The GIF format is one of the most popular formats on the Internet and the most oldest format which is used on the internet. The GIF name is a acronym for Graphics Interchange Format, and was first introduced by Compuserve in 1987. this file format is excellent at compressing areas of images with large areas of the same colour, but it is also one of the best option for putting animation online. What GIF has is Binary, colours ( but no more then 256 colours which are from a palette), its 2D, lossless compression and it can have multiple images. Why is GIF used and when. GIFF is good to use in simple graphics because they do not contain many colours. GIFF can be used when saving animation and is only used online. The only disadvanged of gif is that it only uses 256 colours which makes the work piece limited. One advantage to a GIF is that it uses lossless compression to make an image smaller. This means that no image information is lost during compression. It also has the advantage of making one of the colours in the image transparent to allow the background to show throughOther file formats that are used on the internet are AVI,CSS,DOC,EXE,HTML,JPEG,MID,MPS,MPRG,MOV,QT,PDF,PNG,RAM,RAR,TIFF,TXT,WAV and ZIP.

The BMP which is bitmap pixels have about 24 bits of colour and its not multiple images. BMP is a standard file format for computers running the Windows operating system. Bitmap files are often huge because they don’t normally use compression. This often makes the images unsuitable for web use, but does mean that images will not lose quality if saved several times. Despite this the images can be compressed using lossless compressionWhen does BMP used? BMP is good to use to create background on the window PC and is uses lossless compressions.

PSD is a file format used to create and edit images in Adobe Photoshop. It is a widely accepted format as it supports all available image types – Bitmap, RGB, Duotone, Grayscale, Indexed Colour, CMYK, Lab, and Multichannel. The best thing about Psd format is it can save images in layers. In other words, the image may be opened with Adobe Photoshop anytime at a later date and each individual layer, or part, may be adjusted and edited independently to achieve better effects. Special blending effects may also be achieved using the transparency mask of Photoshop. The maximum size of a PSD file is 30,000x30,000 pixels and may be saved with 16 bits per colour channel.