File Format + Types

                  File formats and types
A pixel is a square full of colour used in raster images.
The resolution of an image is determined by the amount of pixels there are in a set area, DPI (which stand for dots per inch) measures this, the higher the DPI the better the resolution.
The colour intensity of a pixel show how much of a certain colour is shown in the pixel, in comparison to the other colours.
The colour intensity is commonly stored in either a RGB or CMYK format. RGB, is a channel containing the colours red, green and blue. RGB also contains alpha, a channel that shows transparency in a picture, RGB is for storing images digitally. CMYK has the following channels of Cyan, Magenta, Yellow and black. CYMK is mainly used for images you wish to print off.

Compression reduces the files size, it does this by compacting all the information and removing what isn’t needed. Compression is very useful as it allows you save up space on your computer, compressed files are also quicker to send via the internet.

A lossy compression removes any unused data from the file which reduces its size. This also means the images lose quality when zoomed in onto.

A lossless compression technique allows you to keep the quality of the image as the extra data about the image such as layers, is kept. This also means you will be left with a much larger file than a lossy compressed file.

Raster Images pixelate when zoomed in on, as they use these coloured squares to produce the image.
Vestors however do not, as they use co-ordinates to plot the shape, although they have a more limited colour palette.

A raster image uses pixels it generally is used images in which you do not want to zoom in on but you can use a wider range of colours than a vector image.

• BMP- these files were used in old video games as they didn’t require de-compression saving the consoles processing power to be used for more important things, this also meant the files were very big.
• GIF- these files were originally the common image file on the internet, they are small, allow for animations and use lossless compression. However they only have 256 colours maximum so they aren’t very good for photos.Used online for non-photos and small animation loops.

• TIFF- these files are large files stored in a lossless format with all the data intact. Because of the size it isn’t advised to keep many although they are good for high quality pictures. Used for final design. Very good for editing photos.
• JPG- Widely used format for storing images on the web, with enough colours to be sufficent for coloured photos while being smaller than a PNG file as it has no transparency due to the lossy compression. Not very high quality, do not use for photos.

Vestor images use mathematics to make shapes by plotting out the shape with vectors. Because of this you are able to scale the images without them getting pixelated. You are unable however, to produce many details/gradients with the limited colour pallet. 

• PSD- Raster file created by photoshop, it uses a lossless compression format and can save layers, transparency and masks. This means the files are moderatly large, so they are usually used as the source file to be edited, rather than the final design. Is it supported by many other programs other than Adobe programs.
• FLA- Flash animation file, used by adobe. Reduces large graphic files into a smaller file that is better for sharing on the web. Can be used for animation, videos and games like on the website newgrounds.com. Websites with flash generally load slower than those without.

• ai- Adobe Illustrator Artwork, uses unflattened images in a vector format. Editable in Coreldraw, Inkscape and Illustrator it is mainly used for printable media. It saves in a lossless format. As it is a vector image it can be zoomed in indefinitly without it pixelating. Newer versions may have compatability issues.