Examples for Chapter 5

Pixels

Figure 5.1

Download PNG image for Figure 5.1 . Zip archive (only contains 1 file), 132kB.

Open the full size photograph supplied for download in an image manipulation program, preferably Photoshop, and blow the size up on the screen (zoom, do not re-sample) to get an impression of the pixels (but note that it's only an approximation that Photoshop shows you).

Colour

Figure 5.4

Download the image files for Figure 5.4. Zip archive, 19.5MB. (Note that Figure 5.4d is a GIF, the same as the original used in the book.)

Experiment with reducing and changing the colour palettes of these photographs. The easiest way is by using the File>Save for Web... dialogue in Photoshop.

Figure 5.6

Download the image files for Figure 5.6. Zip archive (3 files), 996kB.

The illustration in the book (page 232) does not show the results of posterization and dithering very well, owing to the limitations of printing. Open the three files supplied for download to see the original photograph (a) and the results of reducing it to a 16 colour palette without dithering (b) and with dithering (c). Experiment yourself with reducing the colour palette of a photograph (e.g. by saving as a Gif using the File>Save for Web... dialogue in Photoshop) to different numbers of colours, with and without dither.

Image Maps

Figure 5.24

Download the source for the image maps. Zip archive, 56kB.

Look at the floor plans opens a new window.

None of the links in either version of the image map points to anything. You can observe where the hot spots are by moving your cursor over the image and watching the browser's status bar. The version that uses a elements for hot spots (on the right in the window) only works in browsers, such as Firefox and Opera, which support that form of map, and not in Internet Explorer or Safari, which don't.