June '22

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G R A PH I C S - PR O.C O M 2 0 2 2 J U N E G R A P H I C S P R O 8 1 LOSSY Lossy compression algorithms, while eciently reducing le size, may compromise image quality. For example, let's say that there are four pixels of the same color in the upper right-hand corner of an image. A lossy algorithm might compress the four pixels into one to reduce the le data by three quar- ters. JPEG format is the most common of the lossy compression schemes. Most of the software that saves JPEGs oers a choice of quality levels. (Fig. 2) Lossy compression can dramatically reduce le sizes. Unfortunately, the more compression that is applied, the more degraded the image becomes. For example, the image on the right of Fig. 3 is a highest quality JPEG set to12 and the color transitions are smooth. e image on the left is a low-quality JPEG set to 0, that produces pixel clusters and artifacts. Fig. 2: The JPEG Options dialog box in Photoshop enables a choice of 12 different qual- ity settings. Fig. 3: The image on the left is a low-quality JPEG set to 0 producing pixel clusters and artifacts. The image on the right is the highest quality JPEG set to 12 with clean, smooth color transitions.

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