Whitehead Institute BaRC


Inside WI > BaRC > Graphics > File Formats

Understanding File Formats

You can avoid distorted images and printing errors by knowing which format works best for different types of files. The best format to use is always the format native to the application you are using. You should save and edit your files in this format (in Canvas, save as Canvas format (.cvs), or in Photoshop, use Photoshop format (.psd).)

However, in transfering a file from one application to another or for interpretation by a film recorder or certain printers, using a more universal format is often necessary. It is important to become familiar with the differences between these formats so that you can decide when to use each to get the highest quality output.


FORMAT DESCRIPTION Save in this format if the file is native to:


Back to top

PS (PostScript, .ps)
is the language of printers. When you hit the print button, on the way there the file is translated into the PostScript language.



Back to top


EPS (encapsulated PostScript, .eps)
is a PostScript file with a preview attached, so you can place it in a graphics application and see what you’ve got. The part of the file that goes to the printer is PostScript, and so is very accurate. Most software applications can open EPS files, but the preview quality varies between them. Some applications offer only very low res. EPS previews, so on screen they look blocky, even though they print at a high resolution.




(any vector drawing program)




Back to top


TIFF (Tagged Image File Format, .tif)
This is a bitmap format, which is a good choice for files created in Photoshop. The advantage of this format is that many other software applications can open it, and there is no loss of quality between PSD (Photoshop format) and TIFF. However, TIFF does not support layers, and files saved at TIFF from Photoshop 6 will automatically be flattened. If you want to keep layers, save a copy and keep your original PSD file.






Back to top


format is good at compressing images with large areas of solid color, such as graphics made in Illustrator, FreeHand and Canvas. It usually makes vector images into bitmap images, although PICT 2 retains some vector information. Because it is a compression format, you will notice some loss of quality which will dramatically increase if you try to scale the image after saving as PICT. You also won’t be able to edit vector work after the conversion, but you can open it in Photoshop to make some kinds of color adjustments, etc.

Cross-platform Issues: PCs cannot open Mac PICT files. This is an issue for cross-platform work and should be considered when making PowerPoint presentations.

PowerPoint to film recorder.

Canvas, FreeHand, ClarisDraw, Illustrator to PowerPoint (but not for cross-platform use)

Not recommended for printed output.





Back to top

JPEG (Joint Photographic Experts Group, .jpg)
format is used to compress files for web display. You can choose the amount of compression used to find the right balance between file size and image quality. Files should be saved as JPEG format only once, since each time the file is saved it is compressed further. This is called "lossy compression". This is why it is essential to keep a copy of your original PSD file, so you can always go back to that if you need to make changes or if you need the high-quality version of the file. JPEG works best for screen display and should not usually be used for print as it tends to look fuzzy.
Photoshop (for web display or PowerPoint only)




Back to top

GIF (Graphics Interchange Format, .gif)
is another compression format often used to prepare images for the web. GIF is best used on vector information (hard edged graphics made in Illustrator, FreeHand or Canvas) or text. It produces crisper lines than JPEG, but has limited color capability so it isn't ideal for photographs or keeping colors accurate. When saving in GIF format, use the "adaptive" palette option to get the most out of the limited color options. You can choose how many colors to use in a trade-off between color accuracy and file size.
Canva, FreeHand, ClarisDraw, Illustrator (for web display or PowerPoint only)