June '22

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8 0 G R A P H I C S P R O J U N E 2 0 2 2 G R A PH I C S - PR O.C O M B U S I N E S S S T R A T E G I E S T H E D I G I T A L E Y E | S T E P H E N R O M A N I E L L O IMAGE FORMATS CONFIGURING IMAGE DATA FOR PRINTING AND DISPLAY G raphic formats! What are they? What's the difference between them? How do you know which one to choose when saving an image? Understandably these questions deserve an answer owing to the importance of producing a quality image. Choosing the proper format is critical for congur- ing data to eciently print or publish an image. KNOW WHERE TO GO When choosing the correct format, it's essential to know what your product will be used for. Will it be printed to a large- format printer or on a printing press? Perhaps it will be published on online. Or maybe you're just going to close it and work on it at another time. EXTENSIONS e three-letter extension that is attached to the end of le name is the signature of a format. PDF, PSD, JPG, GIF, TIFF, PNG, EPS are some common extensions that represent how a digital image is en- coded. Technically, image les are com- posed of the same information as text les. At the core level they are binary data — zeros and ones. Physically they are negative and positive charges stored on a piece of magnetic media. Image les can be quite large compared to text les because they contain more data in the form of pixel, color, or vector informa- tion. Encoding a le in a specic format can help store data more eciently re- sulting in smaller le sizes. COMPRESSION Compression is the term that describes how data is consolidated when saved. Compression schemes found in each format oer key features that aect the eciency of a le and sometimes even how an image appears. In some compression schemes, recur- ring data patterns are abbreviated in the code and data that has little or no value might be discarded to reduce a le's size. For example, if several areas of sky are the same RGB value of blue, the value is recorded once and saved with the lo- cation of the other pixels of identical color. LOSSLESS There are two types of compression schemes: lossless and lossy. Lossless compression algorithms pre- serve all the binary information. When the image is saved and then reopened, there is no loss of image quality. Al- though lossless compression sounds ideal, it produces larger le sizes. e most common lossless format is TIFF (Tagged Image File Format) which in- cludes a choice of compression schemes in its dialog box. (Fig. 1) Fig. 1: The TIFF Options dialog box in Photoshop offers a choice of image compression op- tions. (All images courtesy Stephen Romaniello)

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