What is an EPS File, and why is it important for printing?
EPS stands for Encapsulated Post Script. It is an image designed as line art rather than pixels. Imagine painting a line with a paint brush. That line can be blown up to the size of the Empire State Building and never lose its integrity.
Now imagine painting the same line, but with millions and millions of tiny little dots instead of a brush stroke. Once you start enlarging that image…guess what happens…you start to see the dots. These are referred to as pixels. JPEGs, GIFs and PNGs are pixel images or more commonly referred to as bitmaps. They have been optimized for the Web to reduce file size. If you enlarge them, eventually you will see the dots and the images becomes grainy.
Where Do EPS Files Come from?
All logos are first created as line art in programs like Adobe Illustrator or Corel Draw and saved as an EPS – its native form. Web browsers like Internet Explorer, Firefox and Safari (or any browser or mobile device for that matter) cannot read line art. Browsers are built to read pixels. That’s because when you place something on the Web, it’s broken up into a million tiny little pieces and interlaced. Once the image is called by the Web page, the browser pieces all those pixels back together to form the image (remember Willy Wonka?) It does this because tiny pieces are much smaller in byte size and can be quickly uploaded and downloaded by your Internet connection. EPS files are line art, so there aren’t any pixels to piece back together.
What is a JPEG, GIF or PNG File?
So how do you take an EPS file and make it readable for the Web? That’s easy. Save (optimize) it as a JPEG, GIF or PNG – all the file types that browsers can read. Programs like Illustrator use two different types of algorithms when optimizing images: lossless and lossy.
JPEG (Joint Photographic Experts Group) images are compressed using lossy compression and are most commonly used for photographs and video – no limit on colors. During compression, a certain amount of information will be permanently removed from the image to reduce file size. The browser detects the lossy and makes up for it with screen resolution – so, many times you barely notice the loss of data (unless printed). JPEGs do not support animation or transparency.
GIF (Graphics Interchange Format) images were first introduced by CompuServ in 1987 and are compressed using lossless compression. GIFs are limited to 256 colors – most effectively used in scanned images that don’t require many colors. During the compression process, all of the data that is removed from the file is restored once the image is uncompressed. However, because of the color limitation and because PAPER can’t uncompress a file, GIF is not suitable for printing. It, too, is made for the Web. GIFs DO support animation and transparency.
PNG (Portable Network Graphics) are similar to GIFs but with a higher quality form of compression. PNGs support transparency, but not animation.
JPEGs, GIFs and PNGs were created specifically for the Web. EPS files were created specifically for print.
How Do You Open an EPS File?
Although an EPS file can only be opened by postscript programs like Illustrator and Corel Draw, Microsoft Word can actually parse the file.
You can view an EPS file with your computer by simply opening a new, blank Word document. Go to Insert – Picture and select the EPS file on your computer. Once embedded, it will look grainy and pixilated. But that’s just because the graphic viewer in Word can’t accurately piece the information together for the screen – whereas, Illustrator is built to do that.
Go ahead, print the document. You will be astonished to see that the image prints beautifully. That’s because printers use postscript drivers! Remember…EPS was made for PRINTING!
Tips
- Whenever you request a logo, always ask for the EPS file. If it is to be used for the Web, the graphics team can optimize it as a JPEG and at the needed size.
- You CANNOT take a JPEG, GIF, PNG or TIFF file and save it as an EPS. These formats are optimized images. They started as an EPS and were saved DOWN to bitmaps. Remember, we save images into these formats to reduce file size and make them viewable on the Web. They are now pixel images.
- TIFFs are not viewable on the Web. They are optimized images at a higher resolution than JPEG, GIF or PNG. For this reason, sometimes a client doesn’t have an EPS, but they might have a TIFF – that’s the next best thing, although it still will become pixelated when blown up.