Bitmap Vs Vector Images

Bitmap Images

Bitmap images are made up of pixels positioned in vertical and horizontal rows to form a grid. They are same sized tiny squares of individual colour and brightness and they come together and make up what you see on your screen. Most computer monitors display approximately 70 to 100 pixels per inch, depending on the device you are using and the settings, whereas smartphones can display up to 3 times as many pixels as your computer. Pixels are picture elements and their colour will not vary even if you magnify and zoom in to the pixels. Even rounded shapes are made up of the tiny boxes and they make an illusion of a curved line.

Typical desktop icons at screen resolution are usually 32 by 32 pixels which means that there are 32 dots of colour going in each direction and when they are combined they form an image. When the image is enlarged you can clearly see each individual square dot of colour. The white background of bitmap images are individual pixels even though they appear to be one solid colour. Bitmap images are resolution depended which is a measurement of the output quality of an image, usually in terms of samples, pixels, dots or lines per inch. Resolution is usually stated as dpi (dots per inch) or psi (pixels per inch). The terminology varies according to the intended output device. Bitmap images displayed on computer screens at screen resolution are approximately 100 ppi. Common bitmap formats include GIF, JPEG, JPG, PNG, TIFF and PSD.

Vector Images

Vector images are made up Bezier Curves - of individual, scalable objects that are defined by mathematical equations. They always render at the highest quality because they are device-independent. The objects may consist of lines, curves and shapes with editable attributes such as colour, fill and outline and the quality of the object will not be affected if you change its attributes. You can easily modify any number of object attributes, without destroying the basic object. It can also be modified by shaping and transforming it using nodes and control handles.

Because they are scalable images, you can increase and decrease the size of vector images to any degree and your lines will not be destroyed or blurred both on screen and in print. Fonts are a type of vector object. Vector images are usually made up of solid areas of colour or gradients but they cannot depict the subtle tones of a photograph that is why most vector images have a cartoon-like appearance. They are becoming more advanced, today’s vector tools allow you to apply bitmapped textures to objects giving them a photo-realistic appearance. You are also now able to create soft blends, transparency and shading that was always difficult to achieve in vector drawing programs. Common vector formats include AI, CDR, CMX, SVG, CGM, DXF and WMF.

Bitmap versus Vector Image Types

The advantage of vector images is that they are not restricted to a rectangular shapes like bitmaps and they can be placed over other objects with the object below showing through. The disadvantage of vector images is that they are unsuitable for creating a photo-realistic imaginary and you need a special conversion software to convert the image to a bitmap. Once it has been converted, the image loses all the qualities it had in its vector state.