Design 101: Master The Raster
“The Tshirt company is asking for a vector logo. Do we have that?” Chances are if you had a reputable graphic designer create your logo, you probably do. But what is vector? Let’s take a few minutes and explore the two main types of graphic elements, raster and vector. What are their differences, strengths, and weaknesses? When should we be using vector and when should we be using raster?
<center><font color=”#9c9c9c”>***“Raster images are pixels, and vector artwork is math.”***</font></center>
The most common graphic category is “raster”, sometimes also referred to as “bitmap.” This family of graphics is is built using pixels. (For a better grasp of “pixels” see the “[Resolution Revelation](/resolution-revelation).”) Photographs captured with a digital camera, displayed on web pages, or created with pixel manipulation software like Photoshop are made of tiny blocks of color called pixels built on a grid. Examples of file extensions that identify raster images include familiar labels such as JPG, PNG, or GIF. (See “What’s That Format?” for an explanation of these three-digit extensions.) Here are some of the strengths and weaknesses of raster images:
* Complex composition – Because a digital photograph is built with thousands or millions of pixels, each one having different color properties, the output can be beautifully complex. Rich color gradients and fine details can result in amazing graphics that are visually stunning.
* Pinpoint editing – because each individual pixel of a raster image can be individually edited, the artistic possibilities with a raster image are endless. Image manipulation software such as Photoshop or Pixelmator provide an impressive set of tools to push pixels to your heart’s content.
* High compatibility – common raster image formats such as JPG and PNG are compatible with almost any type of application. Because of this they are quick and easy to share and utilize with an endless number of software programs. Most likely any computer built in the last 20 years has software that can open a JPG image!
* Grainy when enlarged – because a raster image is made of pixels, when you increase its size you’re making the computer insert new pixels into the image and make a guess at what color details the new pixels should contain. This most often results in images that appear jagged, blurry, or grainy.
* Large file size – common raster images used on websites are usually a manageable size (for an explanation of file sizes, see “GigaMegaTeraByte”) but larger raster photos or more complex Photoshop compositions can be very large in size, making file management much more cumbersome.
Unlike a raster image which is built of pixels, vector artwork is built of a series of points and lines defined by mathematical equations. Common applications for vector artwork include logos or fonts. Whereas a raster square may have hundreds of pixels, a vector square would simply have four corner points connected by straight lines. Here’s how vector images behave:
* Scalable to any size without quality loss – because a vector is built by math rather than pixels, they are easily scaled to any size while maintaining original quality. There are no pixels to deal with, so the line and point distances are simply recalculated and the software redraws the new size instantly. Whether that logo is the size of a quarter or a football field, it will always be razor sharp.
* Small file size – without millions of pixels to account for, the size of a basic vector file is comparatively small. While vector complexity affects file size, overall they are much smaller than their raster counterparts.
* Flexibility – unlike raster images which are typically flat static pixels, a vector image always maintains its editable qualities. With the proper vector editor, you can always make adjustments to the paths and shapes of your vector artwork.
* Detail limitations – vector artwork does not have the ability to display colors across millions of pixels, so the details are not too deep or complex. While building highly complex vector compositions that approach the realism of raster images is possible, it is certainly not the primary application for vector art. Vectors are most efficient with simple gradients and color fills.
* Lack of effects – common raster effects such as drop shadows, blurs, and similar pixel-based effects are not typically used in vector applications. This does introduce some limitations to vector artwork.
**ProChurch Power Tip**
Do you need your logo redrawn in a vector format? Rather than paying a graphic designer hourly to get it done, consider trying an online tool called [VectorMagic.com](http://vectormagic.com/). The software produces amazing results, and can often create a nearly perfect vector drawing of your logo in minutes!