lesson 21 Working with Images

This lesson includes the following sections: Computer Platforms Used for Graphics Types of Graphics Files Getting Images into Your Computer Copyright Issues

Computer Platforms Used for Graphics The Macintosh started the era of art on the PC in 1984. With its mouse and GUI, the Mac quickly became popular with designers. With the release of Windows, PCs caught up with the Mac in terms of graphics capabilities. Designers routinely use PCs and Macs together. Because of their power and cost, workstations are used only for the most demanding graphics applications.

Types of Graphics Files Graphics files can be saved in many different ways, but fall into two basic groups: Bitmaps Vectors Because graphics programs support so many different file formats, compatibility becomes an important issue for designers.

Types of Graphics Files - Bitmaps A bitmap is a grid whose cells are filled with a color. If you zoom into a bitmap-based line on the computer's screen, you can see the cells (pixels) that comprise it. Bitmaps are sometimes called raster images or bitmapped images. Bitmap software lets you control each pixel in an image. This software keeps track of all the pixels in an image, which may number in the millions.

Zooming in on a bitmapped line

Types of Graphics Files - Vectors A vector is a set of mathematical equations that describe the characteristics of a line or shape. A vector-based program does not see a graphical entity as a set of pixels. Instead, the program sees the entity as a set of start and end points, with thickness, color, and other attributes.

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Types of Graphics Files - File Formats and Compatibility Issues A file format is a standardized method of encoding data for storage. There are many different file formats for graphics. Some programs recognize more formats than others do. Some programs cannot use certain file formats. These files are said to be incompatible with the program.

Types of Graphics Files – Standard File Formats To solve incompatibility problems, designers can save bitmap files in one of several standard formats, which can be used in many programs. The most commonly used bitmap file formats are BMP, PICT, TIFF, JPEG, GIF, and PNG. Most vector programs use their own proprietary file format, but may recognize standard vector formats such as DXF and IGES.

Getting Images into Your Computer Graphics programs let you start an image from scratch, but designers often use existing images, which they load from various sources. The four most common sources of digital images are: Scanners Digital cameras Clip art Electronic photographs

Copyright Issues Copyright is an important concern if a designer wants to reuse art created by someone else. Copyright laws govern the way images can be reused and distributed and thus protect the rights of the images’ owners.

lesson 21 review Identify three computer platforms widely used in graphic design. Define bitmap and vector, and differentiate these file types. List the standard file formats for bitmap and vector images. List four ways to load graphic files into a computer. Discuss copyright issues that arise from the use of computer graphics.

Project due Jan. 4 Choose a figure from textbook where the figure is located within your page range. Your page range is five times your ID number, e.g. B87506027 chooses a figure between pages 131 and 135. Use Painter or other graphics software to paint a figure which is as close to the figure in textbook as possible.