Explanation of Different Graphic File Formats | Different file formats are used for different purposes. There are a number of factors involved. All the elements combine to determine the file type/types that your graphic will need to be created as, or exported to.
- Color Mode (RGB, CMYK, HSB, Web Colors, etc.)
- Resolution (Screen, 300dpi, 600dpi, etc.)
- Purpose (Web, Print, Software, etc.)
- Creation Method (Vector Graphic, Raster Graphic)
Color Mode is the mode that the file is encoded using. RGB is the standard mode for display on monitors, for use with web graphics etc. CMYK is the format that is preferred for four color process printing. Web Colors are merely a palette safe to view on a low color depth monitor, the web palette, often these files are gifs, since the color palette is predetermined.
Resolution is the dots or lines in an inch. The monitor default is 72 dots per inch. Printers will commonly request something in the range of 300 to 600 dots per inch to ensure a smooth, non-grainy image.
Purpose is the reason for the graphic. Are you going to use the graphic to place on your website? Does it need to be a transparent background image? Will you be printing the image on a billboard, a business card, etc.? These are questions that determine the method to create, and save a document.
Creation Method entails the two graphics types, raster and vector. Vector graphics are a product of arcs, curves, lines, fills, and strokes. Think of vector graphics as a large mathematical function that returns a consistently scaled image when you supply it a different input size. Once they are created, they can be resized to any size without losing quality. Logos are commonly created in this format so they can easily be printed at any size needed, and maintain their quality. Raster graphics are usually for a single purpose, a magazine ad, with photographs etc. could feasibly be designed and saved as a raster graphic, if you are sure the size of the image will meet the resolution requirements of the printer. All web graphics are ultimately raster graphics, but are often exported from a vector format original, such as logos on a website.
Below is a list we’ve made to reference common file types, and their purpose. You may not be able to open some of these file types if you don’t have the appropriate software. Most vector-based graphics are only editable with professional editing software, which your local printer or graphic designer will have at their disposal.
.eps (Encapsulated Post Script) - This file could be created in a number of applications, Adobe Photoshop, Adobe Illustrator, QuarkXpress, and Macromedia Freehand to name the most common. These files are somewhat a standard for exchanging vector graphics designers, printers and other designers. .eps isn’t the native save types for many applications, as you’ll see later, photoshop natively saves files as .psd, and Illustrator as .ai files. You can think of .eps as an export to easily readable, yet somewhat editable vector base.
- Colors - These files support several color modes, often you’ll receive a CMYK/Pantone (depending on your printer’s needs) for resizing for a specific printing job, and RGB for resizing for a specific web or other digital purpose.
- Resolution - These files are usually resolution independent, as you can resize them to whatever resolution you need them, or print them directly from the vector program.
- Purpose – As stated these files are usually preferred for print, are commonly used to export .jpg and .gif files for digital use, but are rarely, if ever seen directly used on the web.
- Creation Method – These files are created in vector base. Saving raster graphics, such as photographs, in a vector format does not make the raster graphics resizable without losing quality.
*.fh11 (Freehand 11), and .ai (Illustrator) files are vector format source files, or the format in which the files were originally created, and can easily be exported to .eps.
.pdf (Portable Document Format) - Some printers request this format as it can support vectors and is useful for setting up a printed page, with low risk of altering any of the other graphic elements contained in the file. These files can also be exported from most of the applications that make .eps files. Since Adobe makes Illustrator and Photoshop, it expectedly exports the most true-to-form .pdf files. These files can be opened in professional vector software, but also allow the home user to view them using the free Adobe Acrobat Reader.
- Colors – Same as .eps
- Resolution – Same as .eps
- Purpose – As stated these files are sometimes used for print, and are a very popular for online document publication (tax forms, business and education applications, etc.)
- Creation Method – These files are usually created in vector base. Saving raster graphics, such as photographs, in a vector format does not make the raster graphics resizable without losing quality.
.jpg or .jpeg (Joint Photographic Experts Group) - These files are always raster graphics, and are created for a specific purpose, or exported from a vector based file. They can be viewed in a host of programs, ranging from professional photo editing software, such as Adobe Photoshop, to Mozilla or Internet Explorer. Most digital cameras create RGB .jpg files ranging in size from 640 pixels x 480 pixels to 2560 pixels x 1920 pixels or higher by default. .jpg is a great format for creating and exchanging digital photographs.
- Colors – Will support RGB and CMYK, but without the right software, you cannot view CMYK .jpg files. Most .jpg file creation methods will default to RGB.
- Resolution – As a standard 72 dots per inch for viewing on the screen. The print resolution should be set to achieve the desired quality of print.
- Purpose – Usually for web or digital use, but also used to create printed photographs from a digital camera. Generally, the larger the file, the better the quality. To achieve a very high quality print often requires a very large file, and the size the photo can be increased to is limited by the original file, in the case of a digital camera. Since .jpg offers compression, often an original image can be optimized (altered for faster download) for web use, without losing much quality.
- Creation Method – These files can be created with a scanner, a digital camera, exported from a vector file, or simply created in a graphics program. .jpg offers compression, which allows you to make a tradeoff between file size and file quality.
.gif (Graphic Interchange Format) - These files are very often exports from vector formats, but are always raster. In a scenario where the colors used are limited, they are often smaller than a .jpg file, for the same quality image. .gif files offer two unique options that .jpg files do not, animation, and transparent backgrounds. .gifs can be animated using a series of frames, basically like a flipbook, or traditional cell animation. .gifs also allow for transparent backgrounds, so you can place a web graphic on pages with different background colors or images, without seeing the image’s “bounding box”. Often transparent gifs come out grainy, or show rough edges, and for professional web design, they are not recommended.
- Colors – Will make palette of colors either 2,4,8,16,32,64,128, or 256. You can select specific colors in certain graphics applications, or let the program select the most common for you automatically. The fewer the colors the smaller the file, but you may lose quality if you drop colors.
- Resolution – As a standard 72 dots per inch for viewing on the screen. The print resolution should be set to achieve the desired quality of print.
- Purpose – Almost exclusively used for the web and digital use.
- Creation Method – These files can be created with a scanner, a digital camera, exported from a vector file, or simply created in a graphics program. .gif allows for file size reduction based on the number of colors you choose to index when saving the file.
Contact Ocular Box Studios for all your graphic needs.
| | 2003-08-30 17:59:02 | | Jason Hargett |
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| This was a wonderful experience. They took all of our input and added their expertise. The communication and responsiveness was unsurpassed. We would highly recommend that anyone looking for a professional result with great communication, give them a chance and they will come through. We are already looking at starting the next phase of work and there is no question that they will be doing the work. | -Rub Rocks
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