Pixels vs. Vector Artwork
June 16, 2016
Pro's and Con's of each, and when to use them.
There are two ways to generate artwork. I am sure that you have heard these words before. Most clients have no idea what the difference is and which type will work best with their project. Using the wrong kind could make a big difference in the outcome.
Raster (Pixel) Graphics Overview
A raster graphic is an image made of hundreds (or thousands or millions) of tiny squares of color information, referred to as either pixels or dots. (Technically pixels refer to color blocks viewed on an electronic monitor where as dots refer to the ink dots on a printed piece. But even professional designers, myself indluced, often use these two terms interchangeably.) The most common type of raster graphic? A photograph. The designer’s preferred program for creating and editing raster files? You guessed it: Adobe Photoshop. Popular raster file format extensions include: jpg/jpeg, psd, png, tiff, bmp and gif.
Pros of Raster Images - Rich Detail: Ever wondered what the term “dpi” stands for? It means “dots per inch,” a measurement of how much detailed color information a raster image contains. Say you’ve got a 1” x 1” square image at 300 dpi—that’s 300 individual squares of color that provide precise shading and detail in your photograph. The more dpi your image contains, the more subtle details will be noticeable. Precise Editing: All of those individual pixels of color information can also be modified, one by one. So if you’re a true perfectionist, the level of editing and customization available in a raster image is almost limitless.
Cons of Raster Images - Blurry When Enlarged: The biggest downfall to raster images is that they become pixelated (aka grainy) when enlarged. Why is this? Well, there are a finite number of pixels in all raster images; when you enlarge a photo, the computer takes its best guess as to what specific colors should fill in the gaps. This interpolation of data causes the image to appear blurry since the computer has no way of knowing the exact shade of colors that should be inserted. Large File Size: Remember how a 1” x 1” square at 300 dpi will have 300 individual points of color information for the computer to remember? Well let’s say you have an 18” x 24” photo— that’s 129,600 bits o’ info for a computer to process which can quickly slow down even the faster machine.
Vector Graphics Overview
A vector graphic uses math to draw shapes using points, lines and curves. So whereas a raster image of a 1” x 1” square at 300 dpi will have 300 individuals pieces of information, a vector image will only contain four points, one for each corner; the computer will uses math to “connect the dots” and fill in all of the missing information. The most common types of vector graphics? Fonts and logos. The designer’s preferred program for creating and editing vector files? Adobe Illustrator. Popular vector file format extensions include: eps, ai and pdf.
Pros of Vector Images - Infinitely Scalable: Through the wonders of math (which I don’t claim to understand), vector files can be scaled up or down as much as you want without losing any image quality. Whereas a raster image must guess the colors of missing pixels when sizing up, a vector image simply uses the original mathematic equation to create a consistent shape every time. Smaller File Size: Using our previous 1” x 1” square example, a vector file needs only four points of data to recreate a square versus 300 individual pixels for a raster image. For simple graphics, like geometric shapes or typography, this means a much smaller file size and faster processing speed. Edibility: Unlike popular raster-based formats, such as a jpg or png, vector files are not “flattened.” When you open ‘em back up in a program such as Adobe Illustrator, all of the original shapes exist separately on different layers; this means you can modify individual elements without affecting other objects in the image.
Cons of Vector Images - Limited Details: Because of the mathematically way that a vector remembers data, they are not practical for complex images that require exact coloring. Sure, you can create basic color gradients, but you’ll never be able to match the color detail available in a raster image where each individual pixel can be its own individual shade. Limited Effects: By definition, vector graphics are created from simple points and lines. This means they can’t handle certain styling effects, like blurring or a drop shadow, that are available with raster images.
Here is a great YouTube tutorial video that explains these different types of artwork really well. https://www.youtube.com/watch?v=PJFc3KlEdLM
Let's Talk Print-eze!
May 31, 2016
What to know BEFORE you ask for an ad designed for print.
I know that the things that we need to know before we produce a print piece for you might sound like a bunch of nerd speak. I get it. Sometimes it can confuse the best of designers as well. We found that if we break things down, and try our best to educate our clients on printing basics, we can give you much better service. For instance, did you know that even though the picture appears in full color, looking like a photo, the printer only uses 4 colors to reproduce the image? It's called 4-color process and uses Black, Magenta, Yellow and Cyan. The image is scanned and the software created a halftone image using small dots. When the dots are placed next to each other, in varying sizes, it creates shading that from a distance looks like a smooth blended image. Each of the four colors screen images are then placed at different angles and laid over one another. Your eye automatically blends the dots and screens together making it look like a smooth photograph. When you look at them individually, it's hard to imagine that they can create a true representation of every color. In fact, they won't even come close. The gamut of colors available with this process is very limited, but for printing, it's the best we have. The accuracy depends on the color family. Some reproduce much better than others, as you can see in the photo of the Pantone 4-Color Process Swatch Booklet.
The screened images of each color can be produced using different amounts of lines or dots per inch. If you are young enough to remember, old black and white newspaper photos used to use 45 lines per inch. The dots were bigger and the pictures looks chunky. Some books use 175 lines per every inch. In THAT case, the dots are much much smaller and closer together. This images will look much cleaner and crisp, looking much more like a real photograph. Knowing what line screen the printer is planning on using helps us know how many dots per inch we will need in our digital file to create a quality image in your project. A low resolution file grabbed off of the internet does not have the DPI to reproduce well in print. It will be pixelated and chunky, and we will have an unhappy client.
The next time you call and ask us to lay out a beautiful full page ad, see if you can tell us how it is going to be used and what line screen the printer will be using. We will all be happier in the long run. Make sure you check back to read about width vs. length and vector vs. pixel based artwork.