When a graphic designer creates a masterpiece with imagery, it’s going to be either a raster, or vector image. So what’s the difference? A raster image, simply put, is made up of pixels. A vector image, more complicatedly put, is a mathematical calculation from one point to another. Both formats of graphics are well suited for web and print needs, if you know how to use them!
The Raster Rundown
Raster, or Bitmap, is any image that is made up of pixels. These pixels come together to make photos, and those photos capture all the wonderful memories we hold most dear! Raster images can become finicky to use though if not formatted correctly for your print or web needs. In almost all cases, you won’t be able to stretch the image without losing quality in the resolution. It’s always helpful to know the dpi (Dots Per Inch) and ppi (Pixels Per Inch) of your image in case your printer or web designer has specific standards for their work.
If you aren’t familiar with all of the fun image editing programs that are available, such as Adobe Photoshop, an easy trick to figure out what size your image can print at with a 300ppi, is by multiplying the finished product’s width x 300. So if you wanted to print a mailer that was 4.5 x 6 inches, you would have 6 x 300 = 1800, so your image must be at least 1800px wide to get a print with excellent quality! If you come into a situation where you already have an image, and you want to know that largest size you can print at without distorting (or stretching) the picture, divide the pixel dimension by the resolution required by your printer. So if your printer requires the standard 300ppi, and your image is 2000 pixels wide, you would have 2000 / 300 = 6.67in, which means you can print an image up to 6.67inches wide! Raster graphics are ideal when you have an image with a large amount of detail. With that large amount of detail though, comes a large amount of information for the computer to process, which can slow everything down!
I am a huge, huge, fan of vector. Not only does vector art make for very clean visuals, but it’s also the least fussy to manipulate. On a huge plus side, vector images can be stretched to any size! A small bumble bee in a field of flowers on a postcard, can be transformed into the bumble bee on a mega billboard advertising for the newest honey infused energy drink, with no fractures in the final resolution, and vice versa (you may have to rearrange an eye, or alter a nose, but those are easy fixes).
A convenient feature of vector graphics, is how easy it is to edit. When you open a file that is not flattened in a program such as Adobe Illustrator, every part of the image is on a separate layer, which can easily be manipulated. Because of the way vector graphics remember data mathematically, they do not cooperate as well with images that need a high amount of detail such as exact coloring. Unfortunately, because vectors are made up of mostly lines and dots, they cannot have styling effects such as drop shadow or beveling applied to them.
Like most things in life, both graphics have their ups and downs! Figuring out what type of graphic you are going to use, will all depend on the intentions of your project and what it will require aesthetically. Thankfully with raster and vector, there are many varieties to them both which gives us the ability to constantly make unique and personal products!