Explain in detail both types of graphic images. Explain the differences between them and their respective limitations, making sure to include a definition of rasterizing in your response.

Question

What will be an ideal response?

Answer 1

Graphic images are of two types. Vectors — also called vector graphics — are made up of shapes, lines, and curves that are defined by mathematical objects, or vectors. Vector graphics are high-quality graphics used in illustrations, typography, logos, and advertisements. Vector graphics retain their crisp edges when resized, moved, or recolored because they are made up of individual, scalable lines and objects rather than bitmapped pixels. Therefore, vector graphics are not directly editable at the pixel level. You can change a vector graphic, but not in the same way as you can change a non-vector graphic. When you edit a vector graphic, you change its attributes such as color, fill, and outline. For example, if you create a circle as a shape layer, the vector graphic is generated using the current color scheme and style displayed on the options bar. You cannot edit a vector graphic with the brush or eraser tools, nor can you fill it with color using the Paint Bucket Tool. If you change your mind about the color, for instance, you must select the shape layer and then change the color using the options bar. Changing the attributes of a vector object does not affect the object itself; it merely applies the change as it shapes and transforms the layer along a path. You might have seen or used vector graphics as clip art in page layout and word processing programs.

The other graphic file type is a bitmap image, also called a raster image. Raster images are made up of pixels of color and are resolution dependent; thus, they are appropriate for photographs and artwork with continuous color, such as paintings. Images from scanners and digital cameras are raster images because they need to use continuous color to form the image.

Because vector graphics are drawn instead of compiled from pixels, they are more difficult to edit. For example, before you can modify text — changing the shape of type — you must convert it from a vector graphic to a flat raster image, in a process called rasterizing. When you rasterize, you might need to set the pixel dimensions, color mode, anti-aliasing, dithering, and resolution. The disadvantage of rasterizing is that the image becomes resolution dependent, making it difficult to resize without sacrificing a degree of image quality. While raster images are scaled quite successfully in page layout programs, a permanent change in size is harder to interpolate.