Raster graphics are images that are defined in terms of a generally rectangular grid of pixels or picture elements. Each pixel is a small square of color that, when combined with other pixels next to each other, merge to form a solid image to the eye.

frame formats

Various formats have been developed over the years to store raster graphics. Some of the more popular formats are discussed below, each with its advantages and disadvantages.

BMP – Bitmap graphics (avoid whenever possible)

Easy to create with the built-in Windows Paint program.

Long story hence good universal support.

No compression means the format is lossless.

Create huge files since no file compression is used.

No transparency.

GIF – Graphics Interchange Format (good for the web, on images with less than 256 colors, eg simple geometric shapes, eg bullets for lists)

Creates small files as good compression is used.

Universal support on all platforms.

Transparency supported.

Animation supported.

Color palette limited to 256 per image.

The transparency is only 1 bit, therefore there is no translucency.

JPG – Joint Photographic Experts Group (good for the web, for images such as photographs where color depth is important but lossless formats produce large file sizes)

The lossy compression format produces relatively small files.

Universal support on all platforms.

Visible artifacts at high compression rates.

No transparency.

PNG – Portable Network Graphics (great for the web, but be careful if you use transparency. Good quality and compression tradeoff)

Lossy and lossless compression available.

1-bit and full alpha channel transparency available.

Small file sizes produced.

Poor support in some web browsers for full channel transparency.

Compression is not as good as lossy formats.

vector graphics

Where raster graphics are defined in terms of individual pixels, vector graphics are actually stored as mathematical rules: widths, heights, curves, aspect ratio, proportions. While raster graphics have a set height and width and look pixelated when stretched beyond these limits, vector graphics render in the space allotted to them, so they are resolution independent. log on to http://prowebb.com to see examples of raster vs vector images.

Vector-based logos are no longer based on pixels. It is based on points set at proportional distances, joined with lines and curves, and filled with a solid black color. When drawing curves in vector graphics programs, you define and drag a series of points so that a smooth curve is drawn. This curve is independent of dimensions, but is saved as proportions and proportions so it will scale to any resolution.

Vector artwork can be modified and stretched without having to worry about loss of quality, clarity, or sharpness. Due to their mathematical origins, vector graphics can be easily scaled without distortion.

Vector graphics formats

Once again, there are several formats for storing vector graphics, each with its advantages. It’s important to note that, by their very definition, vector graphics are SMALL compared to raster graphics when it comes to file size. Since they do not store information about each and every pixel, but rather rules for rendering, the file size is greatly reduced. The universally accepted format for vector graphics, particularly when it comes to company logos and sending files for printing, is EPS – Encapsulated PostScript. PostScript is a format developed by Adobe for describing pages on a printer, plotter, or screen. Instead of storing direct data, it stores instructions for the composition of the page. Fonts are stored as individual character vector objects, for example, so they can be printed at the highest resolution the printer can print. Macromedia’s Flash technology is an excellent example of vector graphics at its best: regardless of window size, vector elements in the Flash movie appear sharply smooth and individual frames can even print at high resolution due to the nature of vector based.

Popular raster graphics programs

Adobe Photoshop

Jasc Pro painting workshop

Macromedia Fireworks (tailored to web design)

the gimp

Popular vector graphics programs

Adobe Illustrator

CorelDraw

freehand macromedia

Macromedia Fireworks (tailored to web design)

Popular vector graphics animation programs

macromedia flash

a good question At first glance, vector graphics seems to overcome all the difficulties of raster graphics. They can be resized to any size without loss of quality, and pixelation simply doesn’t happen. The file size is also greatly reduced. However, each format has an individual purpose. A photograph cannot be expressed as a vector graphic because it is simply not vector data. A sunset cannot be defined mathematically, at the risk of starting a philosophical discussion about the world around us. The real world is not vector based. The table in front of you has infinite pixel depth, infinite color variations, infinite relief and texture variations. Vector graphics are reserved for images such as fonts, lines, curves. Complex vector images can be created, but they have been created specifically in vectors. Photographs and complex raster effects, such as lens flare, are defined with pixel-by-pixel lighting and color effects, not vectors.

Logos for companies should always be created as a vector. Why? For maximum use. It’s all well and good to create a great raster logo with lens flares, bevels, and gradients, but what about when it needs to be on a big billboard in a salon? Or, at the other extreme, printed on letterhead. Raster effects are simply not practical when it comes to corporate identities. With vector-based logos, the image will scale to any size and any application; raster graphics would require re-rendering each time a new size was required, not to mention issues with transparency on print and computing platforms.