A Primer of Graphic File Formats

“The print shop is asking for an EPS version of the logo and I only have a JPG…”

“A vendor sent me this AI file and I can’t open it…”

“I need a JPG and can only find this PNG file. Will it work instead?”

Does any of that sound familiar?

There are a staggering number of file formats around these days, so I bet you occasionally come across (or are asked for) a type you’ve never heard of.

Here’s a quick introduction to some of the graphic file types you’re likely to come across:

Web Graphic Formats

JPG

Almost everyone has heard of JPGs. Nearly any photo you download from the web is a JPG. That’s because the JPG format is great for creating photos that look good on screen but have a small file size, which allows them to load quickly. If you’re pasting a photo into an email or posting it on a website, you probably want a JPG.

If you’re printing, though, a JPG may not be your best bet. JPGs can download so quickly because they’ve been compressed. That means that the image quality has been reduced and detail has been removed. You may not notice it on screen, but you may be able to tell when you print it, especially if you downloaded the image from the web. (See previous post on image resolution.)

If the JPG is of high enough resolution (such as the images produced by most digital cameras), you may not notice the compression when printing. However, the file size will be much larger than most JPGs downloaded from the web.

JPGs are rarely the best choice for non-photographic images, though. Compression that may not be noticeable on a photograph, which has lots of shading and texture, becomes much more noticeable on images with flat areas of solid color. For non-photographic web images, GIF and PNG are better choices.

A note about editing JPGs: As mentioned above, JPGs are always compressed when they’re created. Then they are re-compressed every time you edit and resave them. That means that you lose detail and quality every time. If you need to make changes to a JPG (resizing, retouching, color adjustments, etc.), save it in an uncompressed format such as TIFF first, and keep it in that format until you’re certain all your changes are done.

GIF

GIFs are another common web format, and you’ll rarely see them used anywhere else. Unlike JPGs, which can have millions of colors, GIFs are limited to 256 colors per image. That makes them unsuitable for photographs or images with color gradients, but they’re good for simple images with fields of solid color. They also support transparency and animation.

PNG

PNG combines many characteristics of JPGs and GIFs. PNGs can have millions of colors, which makes them suitable for photos. And unlike JPGs, PNGs can have transparent areas. PNG isn’t designed to be a print format, but PNGs are very useful as web graphics and can be used in place of JPGs. I also frequently use them in Powerpoint presentations, because a PNG with a transparent background can be placed against any color of slide.

Print Graphic Formats

EPS

If you’ve ever printed your company logo on T-shirts or other promo products, you’ve probably been asked to provide an EPS version of the logo. EPS is a vector file type, which means that it is made up of curves and points rather than individual pixels. It’s okay if that doesn’t mean anything to you. What you need to know is that EPS and other vector files can be enlarged or reduced to any size without losing any quality. You can use the same file to print a 3 inch business card or a 20 foot billboard, and the results will be equally crisp and clear.

If you need an EPS version of a graphic and don’t have it, you can probably get it from your Marketing department (in the case of a company logo) or from the person who created the original graphic. However, unless you have design software installed on your workstation, you probably won’t be able to open the file yourself. You’ll just need to forward it to the vendor that requested it.

Note: You may also encounter photos in EPS format. This type of EPS can’t be enlarged without losing quality. However, they can be edited and resaved without losing quality, so they’re useful for professional printing.

AI

AI, the vector format used by Adobe Illustrator, is very similar to EPS. You won’t be able to open an AI unless you have Adobe Illustrator installed, but a vendor will probably accept an AI instead of an EPS if that’s all you have.

TIFF

TIFFs are made up of pixels, like JPGs are, so they can’t be scaled the way vector EPS and AI files can. However, they don’t lose quality and detail the way JPGs do. You can make hundreds of changes to a TIFF and resave it every time without affecting the image quality. TIFF is often used as the format for photos that will be professionally printed.

PSD

PSD is the native file format used by Adobe Photoshop. Like TIFFs, PSDs don’t lose image quality when they are resaved. They also maintain a lot of Photoshop-specific features, such as layers and masks. Photoshop users usually keep photos in PSD format until the very end of the editing process, when they’re converted to TIFF or EPS for printing. And these days, it’s not even technically necessary to convert them at the end, as Adobe InDesign (the industry standard layout software) allows PSDs to be placed directly into print files.

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