Article : Understanding Vector Images vs Bitmap Images in Graphic Design

So here's the first step. Let us start to know what is the different between Vector images and Bitmap Images. Both of this type of images are most common type we use in our daily live.

We'll talk about it one by one. so let start with the definition. :).  

BITMAP
Bitmap images (also known as raster images) are made up of pixels in a grid. Pixels are picture elements; tiny dots of individual color that make up what you see on your screen. All these tiny dots of color come together to form the images you see. Most computer monitors display approximately 70 to 100 pixels per inch--the actual number depends on your monitor and screen settings.

Bitmap images are resolution dependent. Resolution refers to the number of pixels in an image and is usually stated as dpi (dots per inch) or ppi (pixels per inch). Bitmap images are displayed on your computer screen at screen resolution: approximately 100 ppi. However, when printing bitmaps, your printer needs much more image data than a monitor. In order to render a bitmap image accurately, the typical desktop printer needs 150-300 dpi. 

Because bitmaps are resolution dependent, it's difficult to increase or decrease their size without sacrificing a degree of image quality. When you reduce the size of a bitmap image through your software's resample or resize command, you must throw away pixels. When you increase the size of a bitmap image through your software's resample or resize command, the software has to create new pixels. When creating pixels, the software must estimate the color values of the new pixels based on the surrounding pixels. By the way. Resizing is different with zoom or in zoom out an image. 

Common bitmap formats include:
• BMP
• GIF
• JPEG, JPG
• PNG
• PCX
• TIFF
• PSD (Adobe Photoshop)

Popular bitmap editing programs are:
• Microsoft Paint
• Adobe Photoshop
• Corel Photo-Paint
• Corel Paint Shop Pro
• The GIMP

All scanned images are bitmaps, and all images from digital cameras are bitmaps.

Bitmap images in general do not inherently support transparency. A couple of specific formats--namely GIF and PNG--support transparency. In addition, most image editing programs support transparency, but only when the image is saved in the software program's native format. A common misconception is that the transparent areas in an image will remain transparent when an image is saved to another format or copied and pasted into another program. That just doesn't work; however, there are techniques for hiding or blocking out areas in a bitmap that you intend to use in other software. For more information about retaining transparency in bitmap images, we'll talk about it later.

Although not as commonly used as bitmap graphics, vector graphics have a lot of virtues. Let's explore them now.

VECTOR

Vector images are made up of many individual, scalable objects. These objects are defined by mathematical equations rather than pixels, so they always render at the highest quality. Objects may consist of lines, curves, and shapes with editable attributes such as color, fill, and outline. Changing the attributes of a vector object does not effect the object itself. 

Because they're scalable, vector-based images are resolution independent. You can increase and decrease the size of vector images to any degree and your lines will remain crisp and sharp, both on screen and in print. Fonts are a type of vector object.

Another advantage of vector images is that they're not restricted to a rectangular shape like bitmaps. Vector objects can be placed over other objects, and the object below will show through. See the example images on this page. The vector circle and bitmap circle appear to be exactly the same when seen on a white background. But when you place the bitmap circle over another color, it has a rectangular box around it, from the white pixels in the image.

Vector images have many advantages, but the primary disadvantage is that they're unsuitable for producing photo-realistic imagery. Vector images are usually made up of solid areas of color or gradients, but they cannot depict the continuous subtle tones of a photograph. That's why most of the vector images you see tend to have a cartoon-like appearance. Even so, vector graphics are continually becoming more advanced, and we can do a lot more with vector drawings now than we could a decade ago. Today's vector tools allow you to apply bitmapped textures to objects giving them a photo-realistic appearance, and you can now create soft blends, transparency, and shading that once was difficult to achieve in vector drawing programs.

Common vector formats include:

• AI (Adobe Illustrator)
• CDR (CorelDRAW)
• CMX (Corel Exchange)
• CGM Computer Graphics Metafile
• DXF AutoCAD
• WMF Windows Metafile

Popular vector drawing programs are:
• Adobe Illustrator
• CorelDRAW
• Xara Xtreme
• Serif DrawPlus

Common metafile formats include:

• EPS (Encapsulated PostScript)
• PDF (Portable Document Format)
• PICT (Macintosh)

Key Points About Vector Images
• scalable
• resolution independent
• no background
• cartoon-like
• inappropriate for photo-realistic images
• metafiles contain both raster and vector data

Okay. So that a start. Lets talk about more how to make vector graphic design and specially using Adobe Illustrator in the next post.

cheers

source Here