Here at Vintage Productions we do a lot of image creation and editing and a common question that we get from clients is: what is the difference in between vector and bitmap and how is that important? Vectors and bitmap are created and function in entirely different ways. Often, the end result might seem to be the same but both types are used for different purposes.
Bitmap images (also known as raster) are basically blocks of colours. They are made up of pixels (thousands of small squares that contain colour information). You have probably come across pixels before when zooming in on photographs.
In this image you can see the little squares of colour that together make up the image. The higher the number of pixels, the better quality of image. When you scale up a vector, what you are actually doing is adding pixels to fill in the gaps in the image. If the bitmap is scaled up too much, it results in a loss of quality and the image often appears blurred. Bitmaps are rich in colour when they are of good quality. In certain cases they allow for smoother gradient, shading and drop shadows. Bitmaps are more common that vectors and can be previewed on almost any device, screen or browser. That is one of the reasons why some web designers use bitmap for web designs. In the coming years, though, this might change.
Vectors are mathematical equations that definite where the edge of a shape is in relation to another. Vectors are made up of lines (paths), points (anchor points), curves and polygons that exist in relation to each other. They do not have an image resolution and can be scaled up with no impact on quality. The main advantage of vectors is that they can be scaled up or down without losing quality. No matter how much you scale up a vector diagrams, it will never get blurred. When a vector is scaled up, the computer automatically uses the equation so as to adjust the size of the image. Vectors usually have smaller file size which is a plus if you have limited storage capacity or need to transfer the images through the internet.
Though bitmap are usually used when it comes to realistic images, some people can create very realistic vector diagrams that could be mistaken for photographs.
Jpg, bmp, png, tiff and gif files are always bitmap file type. You can save a vector as a jpg or a tiff but then what happens is that your vector is rasterised, meaning that it is converted into a bitmap. Eps, pdf, ai, svg and wmf files, that one of our graphic designers like to refer to as container formats, can contain both bitmap and vector images. Note that once you convert a vector file to bitmap file you cannot convert it back.
Uses of bitmap and vector
Here at Vintage productions, we use vectors for icons, logos and text because they allow us to produce images that can be used for different purposes.
For example if we design an icon for a company and that they initially want to use it for brochures but then decide they also want to use it for banners; if we designed it as a vector diagram, this is not issue. The same vector image could be use on a business card or a billboard, it would not matter because vector diagrams do not get blurred when they are scaled up (at least the ones we make).
One of our graphic designers pointed out that he always uses vector whenever possible unless he is dealing with photographs in which case he does not really have a choice. Our 3D team also has a preference for vectors when it comes to the assets, such as logos, icons and stickers that they add to their models. Though our 3D team has a preference for vectors, they do render bitmap when creating 3D images but import vectors when adding details to these 3D designs such as logos and any text that needs to go on the image. That said, we do use bitmap a lot too. As pointed out before, we use bitmap for photograph and for some aspects of web design.
Why is it important to know about bitmap and vector?
It is mostly important so that you can understand why one type is used instead of the other. Bitmap and vectors have different uses (though their uses sometimes intertwine). When working with logos and typography make sure to use vector. When dealing with photography use bitmap (well you do not actually have the choice there). When working with 3D, use vector assets when possible. Most importantly keep in mind that, once converted to bitmap file types, vectors cannot be converted back (well you sometimes can but it is very hard to do), so be careful when you save your files.