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The University of Nebraska-Lincoln has established specific requirements for using UNL and IANR logos and Extension and nondiscrimination statements on University publications (print, web, presentations) and products (signs, promotional materials, etc.). These requirements address size, color and placement restrictions and help assure a single identification and appearance for all UNL resources. To see the most recent UNL requirements and statements, visit the UNL Publications Toolbox, which is available from a link at www.unl.edu/pr
Extension Know How Know Now PowerPoint templates
Spanish Extension Know How Know Now PowerPoint templates
Selecting the Right Graphic File Format for Your Use
Selecting the right graphic file format for your intended use can help ensure you get the best quality possible in the end product. Generally, JPGs and GIFs are used for the Web, higher resolution TIFs are used for print, and EMF files are used for PowerPoint. There are two types of graphic files - bitmapped and vector.
Bitmapped images are made up of a specific number of "pixels" or squares of information. More pixels in the image mean more information, a higher resolution, and a larger file size. Bitmap images are always rectangular in shape. Adjusting the size of the image by stretching it does not alter how much information is contained in the file, it just changes the physical dimensions of the image. If the dimensions are stretched too much, the image quality will decrease and may appear distorted when printed or viewed onscreen. Editing bitmapped images is a time consuming job as each pixel of information must be changed using a photo-editing software program such as Adobe Photoshop. When scanning an image or taking a digital photo, it is important to capture the image at a high resolution so you have enough information in the file for your intended output. Adobe Photoshop, MS Paint, digital cameras, web images, and scanning software are bitmap-based environments.
Bitmapped file formats include TIFFs, JPEGs, and GIFs.
TIFs (or TIFFs) save all the information available and are the best file format for storing or archiving photos. This format is often preferred by desktop publishers and printers because it can provide the highest quality reproduction.
JPGs are a compressed file format. When a file is saved as a JPEG, information (pixels) in the file is discarded to compress or make the file smaller. The amount of information discarded depends on the compression level chosen. JPEG files are used on web pages because of the reduced file size. Often they may not work as well as a TIFF for printing due to the reduced amount of information in the file.
GIFs also are compressed files. When an image is saved as a GIF, fewer colors (fewer than 256) are saved in the file, which leads to a much smaller file size. Since the number of colors is greatly reduced, GIF files are used mainly for line art on the web.
For more information on working with bitmapped images, visit this CIT Web site: Resolution of Digital Images.
Vector-based images store the file information in mathematical equations instead of individual pixels. File sizes tend to be much smaller and the images can have irregular outlines, be ungrouped and easily edited. Resizing a vector image doesn't alter the quality. The physical size of a vector-based image can be increased or decreased in a vector-based program without diminishing its high quality. Before vector-based graphics can be used on the web, they must be converted to a bitmapped file such as JPEG or GIF. CorelDraw, Adobe Illustrator, Macromedia Freehand, and PowerPoint are all vector-based applications.
EMF files are a vector-based file type used for graphics which are to be inserted into PowerPoint. To insert an EMF image in a PowerPoint slide, click on Insert-Picture-From File and locate the file. Click OK. This will add the EMF file to your page. If you get an error message, you will need to locate your Microsoft Office install CD and install Import Filters. The EMF file can be resized to whatever is needed by clicking on a corner handle and dragging.
Both types of applications -- vector and bitmapped -- may be able to import the other kind of file type. PowerPoint, for example, is a vector-based program but can import bitmapped image files (photographs, illustrations, etc.). These image files however, cannot be changed in PowerPoint except for contrast and brightness. Photoshop can import vector images as well.
This discussion is generally limited to the most commonly used graphic file formats. In working with texts and graphics, you'll likely be working with a variety of other formats, including PDFs. PDFs (portable document files) are created with Adobe Acrobat. This format can capture a page layout made up of a variety of formats (text, photos and graphics) and save the document in a single format which can be easily viewed by Adobe's Acrobat Reader. (This software is available free on-line.) This allows for documents to be more easily shared, despite the software used to develop the initial layout elements.
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