What is a Vector?

Pad Printing | Jul 8, 2015

What is a Vector? What is Raster? Why should I care?

Do you remember the line from the movie Airplane, when the pilot asks, “What is your vector, Victor?” Pilots and graphic designers use them. Are you using them? Maybe you’re confused over the difference between the many image file types? You’re not alone! When starting on a new project with a new client, one of the first things you should request from the client is a vector file of their logo. However, that request is often met with blank stares or responses like “can’t you just pull the logo from my website?”  As a professional in the promotional product and apparel decorating business, understanding the importance and role of different file types is essential.

Let’s start making sense of the issue by showing the difference between the two major image types – raster and vector.

Raster images use thousands of colored pixels or individual building blocks to form a complete image. JPEGs, GIFs and PNGs are common raster image types. Almost all of the photos found on the web and in print catalogs are raster images. A common synonym for raster is bitmap.

Because raster or bitmap images are constructed using a fixed number of colored pixels, they can’t be dramatically resized without compromising their resolution. When stretched to fit a space they weren’t designed to fill, their pixels become visibly grainy, blurry or fuzzy and the image distorts. This is why altered photos may appear pixilated at a low resolution. Therefore, it is important that you save raster or bitmap files at precisely the dimensions needed to eliminate possible complications. These types of images are difficult for the average user to manipulate or edit even in professional graphic software programs.

Vector images, alternatively, allow for increased flexibility. Constructed using mathematical formulas and lines rather than individual colored blocks, vector file types such as CDR, AI, EPS and PDF* are excellent for creating graphics that may require resizing or future edits. Your company logo and each of your customers company logos should be created as a vector and saved as a master file. This will allow you to quickly supply other production companies a file that can be used for specific production techniques. For example, a vector file can be easily color separated for screen printing a design on a t-shirt. The same file can also be used for smaller items such as business cards and letterhead, but also on larger surfaces, such as an outdoor sign. Vector files are easy for the average user to manipulate or edit in professional graphic software programs.

You can create a bitmap or raster file from a vector file by simply exporting the file and choosing the news file format. Unfortunately the opposite is not true. When necessary, always create a JPG or PNG for use on the web from a master vector file. Just be sure to save the new raster file in the exact dimensions needed. Creating a vector file from an existing raster image can be a very tedious, time consuming and even frustrating thing to do. It would most likely be better use of your time to outsource this type of work rather than spending two or three hours pretending to be a professional graphic designer.

* PDF and EPS files are generally vector files. However, depending how they were originally created, they can be either a vector or a raster file – or both!