PGDEL/DECP03/Unit1/16

 Unit 3.1 Multimedia Basics  File Formats

Graphic images may be stored in a wide variety of file formats. In choosing a format, you should consider how and where the image will be used. This is because the application must support the file format you select. Some formats are proprietary while others have become universally supported by the graphics industry. Though proprietary formats may function perfectly in their own environment, their lack of compatibility with other systems can create problems. In the Macintosh environment, the PICT format, a vector-based file format, is the image format supported by almost all Macintosh applications. Recently, the Windows environment has standardized on the BMP file format. Prior to this, there were multiple file formats under DOS that made it difficult to transfer graphic files from one application to another. The most common file formats are described below.

TIFF (TAGGED IMAGE FILE FORMAT) The TIFF file format is probably the most widely used bitmapped file format. Image-editing applications, scanning software, illustration programs, page-layout programs, and even word processing programs support TIFF files. The TIFF format works for all types of images and supports bit depths from 1 to 32 bits. In addition, TIFF is cross platform. Versions are available for the Mac, PC, and UNIX systems. The TIFF file format is often used when the output is printed.

BMP (SHORT FOR BITMAP) The BMP format has been adopted as the standard bitmapped format on the Windows platform. It is a very basic format supported by most Windows applications. It is also the most efficient format to use with Windows.

GIF (GRAPHICS INTERCHANGE FORMAT) CompuServe created this format. Consequently, you may see it listed as CompuServe GIF. It is one of two standard formats used on the Web without plug-ins. It is the method of storing bitmaps on the Web. The GIF format only supports up to 256 colors.

PICT/PICT2 (SHORT FOR PICTURE) These are formats for the Macintosh. They are generally used only for screen display. Some Mac programs can only import images saved as either PICT or EPS. Unlike the EPS format, PICT does not provide information for separations, which means graphics saved with this file format will be smaller than EPS files. PICT2 added additional levels of color to the PICT format. JPEG (JOINT PHOT04GRAPHIC EXPERTS GROUP) This format creates a very compact file. Because of its small file size, it is easy to transmit across networks. Consequently, it is one of only two graphic file formats supported by the World Wide Web without plug-ins. Do keep in mind that in order to make the file so small, lossy compression is used when a file is saved or converted to this format. This means pixels will be removed from the image. JPEG files are bitmapped images.

CD (PHOTO CD) This is Kodak's Photo CD graphics file format. It is a bitmapped format that contains different image sizes for each photograph. Apart from the above commonly used formats, there are also many proprietary formats. If you plan to transfer files from application to application, consider using the most common file format supported by all of your applications. If you get stuck because an application does not support a graphics file format, graphic conversion software is available to help you change the file format so that you can import and export graphic images from almost any application to another. Keep in mind, that in most situations, commercial image providers are only selling the rights to use the image, they are not selling the image itself. In other words, they may sell you the right to use the image in one multimedia application, but the image does not become your property. If you want to use it again in a different multimedia application, you may very well have to pay another royalty. The agreements vary depending on the image, the original artist, and the commercial image provider. Take caution and read the licensing agreement carefully before you include an image from a CD or the Web in a multimedia application. Just because you purchased the CD or were given access to the image on the Web, that doesn't necessarily mean you own it.

Copyright

If In Doubt, Assume An Image Is Copyright Protected. The 1976 Federal Copyright Act stipulates that copyrighted images are property of the creator from the time they are created to 50 years beyond his or her life. If the creator is a corporation or business, the image is property of the creator up to 75 years after publication or 100 years following creation, whichever is shorter. After the copyright period has expired, the image becomes public domain. Public domain images can be manipulated and used without permission from the artist and without having to pay the artist any royalties for using them. When images or other copyright protected works are used strictly for instruction and research in an educational setting, copyright permission may not be necessary. This exclusion is referred to as a fair use policy. There are many factors that determine when this exception applies and when it does not. If you are uncertain as to whether or not an image is copyright protected, don't take chances; assume that it is copyright protected and seek the advice of a legal expert.