Raster vs.Vector! Sounds like an epic battle between two comic book villains, doesn’t it? But no: raster and vector are simply two basic types of image files. And figuring out which one to use doesn’t have to be a battle at all.
The fundamental difference between raster and vector graphics is in the method the files’ data use to form the image. Each method has advantages for certain kinds of images.
Raster images, also sometimes called bitmap images, are made up of pixels: tiny squares of color that combine to form the image. Usually, these pixels are so small that you don’t perceive them individually – you just see the image they form. But if you zoom in extremely close on a raster image, you’ll see it’s really just a bunch of squares.
Raster images can contain many thousands of tiny squares of color.
Resolution is a measure of how many pixels are in a given area of an image. The more pixels, the more detail is visible in the image. When resolution gets too low, the eye begins to perceive the individual squares of color, lending the image a blurry or fuzzy look. This is typically something to avoid!
If the resolution is sufficient (which can depend on the medium; printed images require higher resolution than ones viewed on a screen), raster images excel at reproducing photos. They don’t do as well with line art or smooth curves, unless resolution is very high.
Vector graphics are composed of paths: The file describes specific points in the image and the paths that connect those points. This method allows vector graphics to be scaled to any size, because these points and paths are simply redrawn according to their mathematical relationships. Because there are no pixels, resolution is not an issue – no matter the size, vector graphics will always look just as smooth as the original.
Points and the paths that connect them make up the underlying structure of a vector image.
This is why vector files are usually preferred for logos. They can be enlarged to any size without losing quality – and even if they’re enlarged to huge proportions, the file size remains small!
The downside to vector graphics is that they don’t do as well with complex imagery that contains subtle gradations of tone or color – which means most photographs. There are always exceptions, but as a basic rule, stick to vector logos and illustrations, and let photos be raster.
–Austin Stahl, Art Manager, Network Media Partners, Inc.
Do you know your PSDs from your PDFs?
May 24, 2010
There are a lot of file extensions to wade through out there. Here’s a run down to help you better navigate the production waters
To the uninitiated, the wide variety of graphics files out there can seem like an incomprehensible alphabet soup – and new file formats seem to pop up all the time. If you don’t know your PDFs from your PSDs, here’s an overview of some of the most common formats.
Video/Animation files
FLA (.fla)
Native Flash documents – these are files that can be created, opened and edited in the Adobe Flash application. They can include animation, video, and interactive elements. An FLA file would never appear on the web or in a digital publication: It is not the final product, but rather the working file that can be opened and edited again and again. It can only be opened in the Flash application.
FLV (.flv)
Flash Video. FLV files contain video content, which can be played back by Adobe Flash Player on the web. Many websites, including YouTube, use the Flash Video format. FLV files can be played back on their own, or embedded within a SWF (see below).
SWF (.swf)
Stands for Shockwave Flash, or alternatively Small Web Format. SWF files contain a finished animation created in Flash. They are designed to be small enough in file size to be published on the web. A SWF file is not fully editable the way a FLA file would be, but rather is the final product that appears on the web. SWF files originally contained only vector animation, but can now contain Flash video (FLV) elements and interactivity.
AVI (.avi)
Audio Video Interleave. AVI is a format that contains audio and video. One of the earliest multimedia formats, it is still in use, though less common.
Other image files
PDF (.pdf)
Portable Document Format. PDFs are files that can contain many different types of data – text, images, and more – in a single compressed file. They can be viewed in many different programs, as well as on the web.
EPS (.eps)
Encapsulated PostScript. EPS files are image files that can contain either vector or raster image data, or both. They are the most common format for vector graphics, such as logos.
TIFF (.tif)
Tagged Image File Format. TIFFs are bitmap (raster) image files, typically used in print, not on the web.
JPEG (.jpg)
Joint Photographic Experts Group. JPEGs are bitmap (raster) image files that are often used on the web. They are compressed for smaller file size – some information is actually thrown away in order to reduce the amount of data contained in the file. The compression used in JPEGs works best with photographs, rather than images with areas of flat color.
GIF (.gif)
Graphics Interchange Format. GIFs are bitmap (raster) image files that are often used on the web. They can support animation by displaying a series of images within one GIF file. GIFs can also be static. (To view the animation in an animated GIF, you need to view it in a web browser.) Because of limitations on the number of colors they can use, GIFs are better suited to simple images with areas of flat color (such as logos) than to complicated photographic images.
Other native files
“Native” files are files that are specific to one application or program, and are designed to be opened and worked with in that application only. Typically, in order to open a native file, you must use the application in which it was created (usually, even the same version or newer of the application is required).
PSD (.psd)
Photoshop Document. Must be opened in Adobe Photoshop. PSDs can contain many layers and effects that remain editable.
INDD (.indd)
InDesign Document. Must be opened in Adobe InDesign. InDesign documents are the main layout file for many print pieces (and occasionally digital pieces as well) and often are linked to separate image files and fonts that must go along with the INDD.
AI (.ai)
Adobe Illustrator document. Must be opened in (you guessed it) Adobe Illustrator. AIso can contain many layers and effects that remain editable.
QXD (.qxd)
QuarkXPress Document. Must be opened in QuarkXPress. QXD files are layout files, similar to INDDs.
Note: File formats are typically referred to by their acronym (all caps: JPEG) but sometimes instead are referred to by their extension (dot + lowercase: .jpg). The extension is what you see at the end of the filename. Either one is OK as long as you’re consistent, but it’s probably better to use the acronym.
There are many more file types, but these are among the most commonly used in the design and publishing worlds. If you’re a non-designer, familiarity with these terms will make it easier to communicate with the designers you encounter in your work. They’ll appreciate it!
–Austin Stahl, Art Manager, Network Media Partners, Inc.
For his next act, Austin will uncover the mystery of raster versus vector…
April 27, 2010
New standards for the USPS droop test have us all wondering if our pubs will stand up to the test. Your mail house will tell you for sure, but here’s the basics for a DIY droop test you can do at your desk:
For magazines longer than 10 inches:
Extend the magazine over the edge of your desk by 5 inches. If the pub droops more than 3 inches, you have failed. Stop. Do not pass Go. Do not collect $200. Call your mail house.
For magazines shorter than 10 inches:
Extend the magazine over the edge of your desk by half its length. If it droops less than 2 inches, you are good to go. If it droops more than 2 inches, call your mail house.
For more information, download this bulletin from the USPS and find diagrams on page 5.
FINE PRINT: Only your mail house can tell you if you pass the droop test. Ask your mail house if the droop test is right for you. Some publishers have experienced shortness of breath and anxiety while taking the droop test. If you experience any of these symptoms, stop taking the DIY droop test and talk to your mail house immediately.
March 30, 2010
