File Formats

A pixel is a small square that is coloured and used in Raster images. There are thousands of pixels within a single picture and the aim is to make the pixels not individually visible within a picture this makes the image look more fluid. The image resolution is directly related to the pixels. The image resolution is the amount of detail an image holds and the smaller the pixel size the higher the resolution and more clear the image will be. The resolution is how many pixels are in a certain area, usually per square inch. The pixel colour intensity is how much colour is within the pixel. As they only use a certain number of colours when the pixel is formed they must use different intensities to change the outcome colour to fit a bigger palate. The common ways the pixel colours are stored are either in RGB which stands for Red, Green and Blue.  The more in depth version is CMYK which stands for Cyan, Magenta, Yellow and Black. This is also the colour palate used for printers and so for printing images this is a good one to use.

Compression reduces the files size of an image or file. It does this by compacting all the information and removing what is not needed. This is useful for storing digital graphics because you are able to make the image size smaller without effecting the image itself, potentially saving you a lot of hard drive space. The information that is removed can either be lossy or lossless. Lossy means that the information that is removed is permanently removed from the image, and so if you cut off a piece of an image, this will be permanently lost on save. Whereas lossless refers to the opposite, in that the information can all be restored and re-edited whenever you require.

A raster image is also known as bitmap, these are quite large file sizes but can accurately produce coloured photos and images. These use small coloured squares in pixels to create an image, which means that making coloured images are a lot easier. Examples of these are:

·         BMP (Bitmap) – These files were used a lot in old video games (PS1, PS2, NES, Handhelds), These images are not compressed at all which is why they were used in the video games industry for a long time. These images will be in high quality due to the lack of compression.

·         GIF – This image file has lossless compression and so they keep all the information of the original file. These are not ideal for photos as they can only hold 256 colours maximum and so blending colours will not work. However this file type allows 
      for animation.

·         Tiff – These support high quality images and saves them in a large file size. This is popular amongst graphic artists and the publishing industry as they are incredible high detailed and 
      will mostly deal with lossless compression.

·         JPG – JPG or JPEG is the most common file type. It uses compression to reduce file sizes but can lose a lot of detail due to making a smaller size for the file.

A Vector image is made up of co-ordinates and mathematical equations to create an image. The file sizes are incredibly small due to the information being only co-ordinates and calculations, which also means that upon zooming closer into the image the picture will not blur as it is able to simply re-calculate the image. However these do not accurately show colours and will only use block colours with no blending. Examples of these are:

·         PSD -  A PSD file is the default image file for Photoshop. This like many others have the bonus of using lossless compression. However, The image is in very fine detail as it is used to save the image for editing and so they come out in a HUGE file size.

·         PNG - PNG files have lossless compression allowing for alot of editing. They also include transparency which means that you can have a transparent background on an image instead of a full white one. The downside to this file type is that it only supports RGB colours which means it is slightly more limited than others that can use CMYK, however it is still good for use on photos.

·         TARGA - TARGA files are incredibly big files, which means they have alot of detail and is used in a lot of textures in gaming. They are very flexible to change with the use of Alpha.