9 File types and their uses
As a Graphic Designer and Illustrator, I work with a lot of clients, on a lot of projects, with a lot of files. Perhaps the single most common thing my clients ask of me is to explain the different files I send them at the end of a project. Now, after a couple of these requests, I started emailing an explanation with the files themselves but felt like it was enough of a grey area for people, that it would be worth writing about here.
So, “why do I need all these files?” Good question. The answer? Because you’re going to use the design for various uses and on different platforms.
Contrary to popular belief, a JPG isn’t the only file of any use, a Word document doesn’t create an up-to-scratch logo, and changing the extension name of a document does not convert it. You need to start with a reliable source file, then export it for each different use.
AI: Adobe Illustrator File
An Ai is a source file that holds vector-based artwork in its rawest form, in multiple layers and artboards -it’s capable of holding a lot of uncompressed information. Whilst it’s capable of holding raster-based graphics, it generates vector-based shapes.
In simpler terms, an AI file is basically the building blocks of an illustration that a designer can come back to edit/change/update or use as the base of a new document. The graphics in an AI file can be exported into many of the files listed below and an AI is one of the most flexible source files to work with. It’s commonly used to create logos or illustrations.
If a designer provides you with an AI file, you probably won’t have the program necessary to open it, but you should keep it safe for future use.
PSD: Photoshop Document
A PSD is somewhat similar to an AI file in the sense that it’s also a ‘live’ file with a lot of un-flattened information; that means graphics may reside on many different layers, each with their own modifications. The primary difference between a PSD and an AI is that a PSD is raster-based and an AI is vector-based.
Whilst Photoshop can be used to create content from scratch, this is really where Illustrator shines. Photoshop is typically used for photo editing or graphic manipulation, i.e, merging existing graphics to create something new.
INDD: InDesign Document
An INDD is an Adobe InDesign file, another source file with active, un-flattened information however InDesign is a DTP (desktop publishing) program that focuses on layout and stylistic formatting rather than content creation. It would typically be used for brochure design or formatting business cards ready for print.
PDF: Portable Document Format
A PDF file is a file that we’re all familiar with; it’s a flattened preview of a document that’s designed to be easily transferred (via email, memory stick, etc) but not easily edited. However, there’s also such a thing as an Interactive PDF where the creator can generate fields (text boxes, checkboxes, signature fields, etc) that don’t get compressed down and remain editable by anyone viewing the PDF.
It’s probably one of the most widely used document types (particularly within an office setting) and its main purpose is to easily share and display information (text, images, etc).
JPG: Joint Photographic Group, pronounced “jay-peg”
Everyone has heard of a JPG. Literally, everyone. It’s a lossy raster-based photo file used within digital photography. A JPG is used to compress a photo file at a 10:1 ratio to provide a quick upload/download for use online whilst supporting millions of RGB colours. That means, if the source image is 10MB, the compressed JPG should be roughly 1MB… which leads us to the biggest problem with the JPG.
Oftentimes, you’ll see a jpg that has been edited and compressed, then edited and compressed, then edited and compressed, and so on. It’s like photocopying a photocopy of a photocopy; each time you’re going to notice a decline in quality. This is why the internet is filled with tiny little jpg files that are so pixelated. And the process is irreversible (so I hope you have the good sense to duplicate the original before making an edit). Whilst a jpg is efficient at what it was designed to do, it also comes at the cost of losing data.
PNG: Portable Network Graphic
A PNG is essentially a more sophisticated, lossless JPG (albeit, a larger file) used on the web. I say ‘more sophisticated’ because it supports transparency where a JPG doesn’t (hence, you get that ugly white blocky background when you download a jpg). The biggest advantage of a PNG over a JPG is that it’s lossless, so it doesn’t suffer the quality decline we just spoke about.
A PNG is excellent for most web-based graphics (think logos, masked images, text-based images) and is the file type I usually encourage my clients to use across the board on the internet for a professional, crisp result.
EPS: Encapsulated Postscript
An EPS is a vector-based file that is the standard file format requested when something is going to be printed (especially if it’s going to be blown up and printed on a large scale). It supports transparency, is widely used, and is compatible with pretty much every vector-based software and printer.
You may not need the quality of an EPS to get your design printed, but to be on the safe side, I tell my clients to always send the EPS whenever they want something printed.
GIF: Graphics Interchange Format, pronounced “jiff”
A GIF is a sequence of animated bitmap images that play on a loop - you’ve almost certainly seen them online, in a forum, been texted one, etc. It’s the modern-day flipbook. The file size is typically pretty small because there’s not a lot of information stored and, as a designer, I typically work with them for email footers or as a digital banner.
TIFF: Tagged Image Format File
A TIFF is a bitmap file designed to preserve quality (it doesn’t compress like the JPG). It supports layers and transparency and is compatible with photo editing/manipulation programs like Adobe Photoshop however it's an in-progress file. It’s big and bulky and isn’t suitable for web use because the size of it would be a nightmare to manage.