Raster and Vector Images

Raster and Vector

There are two different ways to generate images, Raster and Vector. They are both different ways to create images. Even though Raster is the more common of them both, Vector is actually a better method.

Raster (bitmap).

Raster images are made by pixels in a grid, each pixel is assigned a specific 

Example of what Raster images look
like normal & zoomed.

co-ordinate. Each pixel is also given an RGB colour (mixture of Red, Green & Blue, each colour ranging from 0-255) which is sent to the co-ordinated pixels, when all pixels have their colour, it creates an image on screen. The more pixels there are on the screen, the more precise the RGB can be so the image looks better.

When magnified far enough (depending on the image resolution), you can see each of the individual pixels that make up the image. This, when used in low resolutions on video games, can make the game look really bad.

Common file types that use Raster generation include JPEG, TIFF, GIF and BMP.


Vector.
Vector images use a very different method to create an image. Vector images use mathematical points in space as references, then connects them with lines.

This is the far superior method of generating images. This is because, for example, if it was scaled to the size of the world, it will still be as clear as if it was the size of a normal Full HD image (1920x1080).

Vector compared to Bitmap (Raster)

Vector images are mainly used in mobile devices, particularly touch screen. This is because the co-ordinate based image creation helps with the relation between the input device (touch screen) and the image displayed.

Common file types that use vector generation include PSD, WMF and FLA.

File extensions and file compression

File Extensions.

When saving a file on programs such as Adobe Photoshop, there are several different types of of files it can be saved as. Different file extensions have different properties, like:

JPEG - This does not have the best quality, but fairly good compression. It is a 'lossy' format, meaning it will lose quality each time it is saved. It is 24-bit colours (16.4 million colour possibilities). This format is still widely used because it's simple, anybody can view it, and it's small file size means it is quick to upload to websites and quick to load when viewing the website.

PNG - Improvement on the GIF and JPEG formats. Low compression, but it is a loss-less format means it retains it's full image quality no matter how many times it is saved. Supports 48-bit colours (1 billion colour possibilities). Does not support CMYK, so commercial printers cannot print this file type.

There are a lot more file extensions available for use, these include:

• PSD
• GIF
• TIFF
• EPS
• PDF

File Compression.

File compression does a number of things. The main function of compressing a file is to reduce the size of the file (e.g. from 1 GB to 78 MB) depending on the type of compression. However, in order to acheive high compression, image quality must be sacrificed.

If it is going to take a few days/weeks to complete an image, it is generally a good idea to save as a loss-less format while working on it and when the image is complete then save it as a format such as JPEG (unless it specifically has to be a different type of file).