That was my first day in the class, when my teacher explained the two major types of graphics and the difference between them. But unfortunately, most of the students including me, were new comers in the field so we couldn't understand the point thoroughly.That is precisely why, when I enlarged an image and it got completely deformed and blurred, I got a bit anxious about my level of understanding regarding resizing an image. I tried to resize the same image again and again but no improvement made.The next day I went straight to my teacher and told him hesitantly that I couldn't pick his points regarding resizing an image and I need more explanation about the same topic. My teacher asked the rest of the class whether they had any issue concerning the previous lesson too. To my great surprise, almost 80% students admitted that they had the same issue I had been bothering myself with. My teacher smiled and revealed that he had been expecting the same complaint from the class for the very first day.
It’s obvious, if you are a new comer in the field of computer graphics with not enough knowledge, and you are having fun with Photoshop, your instructor teaches you how to enlarge the size of an image, you think it’s quiet easy, but what are you supposed to do when you don’t have the proper result after following the instructions of your instructor?
Well…. In my opinion, there is no need to worry about that .If your image has lost its features after enlargement, it’s not your fault. The only thing you are supposed to do is to understand the cause. And cause is nothing but the resolution of the image. In order to understand the term Resolution it is better to understand the main types of graphics and the difference between them.
Types of Graphics
There are two main types of graphics:
- Bitmap or Raster Graphics
- Line Art or Vector Graphics
Bitmap or Raster graphics
Bitmap or Raster graphics are composed of a host of small colorful rectangular dots. These dots are called pixels. Quality of an image that is usually referred as ‘resolution’ depends on how smaller and how closer these dots are. In fact, resolution of an image is measured in dots-per-inch (DPI). It’s mean, more and more smaller and more and more closer the dots, more and more better the resolution of the picture, less and less smaller and less and less closer the dots, less and less better the resolution of the picture. That’s the formula better to be kept in mind.
Further, in these types of graphics, you must have to be careful while enlarging your images because your action might distort pixels and you are not likely to have a good looking image after resizing it. So it’s always good to have high resolution image for enlargement experiments.
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| Raster Image: Gets blurred after enlargement |
We come across different image editors when enter the field of computer graphics. There are a few image editors (e.g. Photoshop, Ms Paint, Painter, GIMP and Paint.Net) are used to edit pixels so these are called raster-based image editors.
Most of the monitors and printers which are being used these days are raster devices, meaning DPI can be set before having display or print through these devices. These devices don't create any good or bad effect on the pixels of the image but simply determine the required number of dots which are to be used to print or display all pixels. DPI is usually recommended to be kept between 72 to 300 because, if DPI is set too high the details of the image might be lost and if DPI is set too low the picture will get blurred and soft.
Vector or line art graphics
In vector graphics, geometrical primitives e.g. lines, points, different polygonal shapes and curves are used to represent an image. Unlike raster graphics (which are pixel based) vector graphics based on vectors which are often referred as strokes. Each stroke or path has a starting and an ending point. A path or stroke can have any geometrical shape (it can be a line, angle, curve or a polygon).
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| Vector image: Retain it's features after enlargement |
You can change the size of vector based images according to your requirement without destroying their features and losing their clarity. Clip arts, monograms and logos are often made by using vector graphics instead of raster, since these can be scaled quiet easily, so these are fit, whether you want to use them on business cards or on billboards. Further, vector graphics are used in many Flash animations (cartoons etc) too.
There is another benefit associated with vector graphics, that is they take up less space than raster graphics. CorelDraw, Adobe Illustrator, Xfig, Macromedia Freehand etc. are very well known examples of image editors based on of vector graphics.
I hope this post will be proved helpful for the beginners in the field. if so, kindly don't forget to subscribe your comments.
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