Anyone who works with graphic files is faced with two options: vector and raster images. Each of these formats has pros and cons. Non-specialist customers often do not understand the principles of both types and the difference between them: when a vector file is needed, and when only a raster file is needed. In the article we will tell you what these graphic data formats are and how they differ.
Bitmaps
A raster is any file depicting the world around from nature: scanned drawings, photographs, pictures made in computer programs – at least in the same Paint. The elementary unit of such files is a pixel: a very small square filled with a certain color. The number of pixels per unit length (most often – inches, in English) determines the resolution of the bitmap – dpi.
Raster images have the following properties and characteristics:
- For sites, the minimum resolution is 75 dpi: less – the quality will be too low, more – the page will take a long time to load.
- Printing requires a resolution of 150 to 300 dpi – with fewer pixels per inch, the image will be fuzzy, blurry, grainy.
- Raster scaling is extremely undesirable: when the image is enlarged, pixels become visible, the image is divided into colored squares.Reducing the raster is less problematic, but if you make a very small file from a large file, the contours and fine details will be greatly deformed.
- A raster is used in design, decoration, illustrations and other similar areas if it is necessary to convey a complex natural object as realistically and fully as possible, for example, a portrait or landscape with an abundance of small details. For raster graphics, there are practically no restrictions on the types of images.
There are many raster graphics editors, from very simple ones like Paint to professional ones: Adobe Photoshop or Corel family programs: Photo-Paint, Paint Pro, Painter. The most popular format (extension) is JPEG (.jpg, .jpeg, .jpe, .jfif). Also often used are BMP (.bmp, .dib, .rle), TIFF (.tiff), GIF (.gif), PNG (.png) and a number of others.
Vector images
Vectors are files created in special programs using a complex set of tools. They consist of objects and contours, the relative position of which is described by mathematical formulas. In vector graphics editors, it is possible to form complex multi-color multi-component images. A graphics tablet greatly increases the complexity and realism of vectors.
Vector images have the following properties and characteristics:
- they can be freely scaled in any direction: that with an increase, that with a decrease, the clarity of the lines will not decrease, and graininess will not appear;
when scaling vector drawings, it is important to convert contours (outlines) into objects or activate the scaling function with the object (check the box); - vectors can be exported to raster formats by specifying the required size in different units of measurement: pixels, centimeters, inches, etc.;
- a vector image, unlike a raster image, can be significantly changed at any time: remove or add details, recolor, change proportions.
- The vector is used in the same areas as the raster, but in the case when the possibility of free qualitative and quantitative change is much more important than the realism of the transfer of the surrounding world. Simple elements, emblems and coats of arms, advertising products, man-made objects, interiors, geographical maps are formed in the vector.
There are fewer vector graphics editors than raster graphics editors because they are more complex and their scope is more limited. The most famous programs are Adobe Illustrator (more professional) and CorelDRAW (suitable for amateurs and beginners). The main formats and extensions are AI (.ai) for Adobe, CDR (.cdr) for CorelDRAW, SVG (.svg).
Comparison of vector and raster
The advantages of raster images include high realism and photographic quality of the picture, relative ease of obtaining (camera on a smartphone, the simplest camera, etc.), natural colors and tone transitions.
The disadvantages of raster images include a large file size with high definition resolution, limited changes (only minimal editing), undesirable scaling, loss of quality when enlarged or reduced.
Raster files are used to store amateur and professional photography, digitize paintings, and create book illustrations. Most of the images around are just a raster. They can be supplemented with vector elements.
The obvious advantages of vector graphics are the possibility of significant changes in the drawing, unlimited scaling without loss of quality, a small file size even with a large and complex image, ease of exporting to raster formats.
The main disadvantages of a vector image are its sketchiness, simplified colors that are not suitable for the color transfer of real objects of the surrounding world, the relative complexity of creation (you need a program and the ability to work in it).
However, these shortcomings are partially compensated by the creation of a vector from a graphics tablet. Drawing in the editor by hand rather than with the mouse makes it easier, but it’s still difficult to build a real detailed object, and the file will come out large.