Glossary | 551
highlighting box
A rectangle with eight handles that encloses a selection in an image.
histogram
A histogram consists of a horizontal bar chart that plots the brightness values of the pixels in your bitmap image on a scale from 0 (dark) to
255 (light). The left part of the histogram represents the shadows of an image, the middle part represents the midtones, and the right part
represents the highlights. The height of the spikes indicates the number of pixels at each brightness level. For example, a large number of
pixels in the shadows (the left side of the histogram) indicates the presence of image detail in the dark areas of the image.
hotspot
The area of an object that you can click to jump to the address specified by a URL.
HSB (hue, saturation, brightness)
A color model that defines three components: hue, saturation, and brightness. Hue determines color (yellow, orange, red, and so on);
brightness determines perceived intensity (lighter or darker color); and saturation determines color depth (from dull to intense).
HTML
The World Wide Web authoring standard comprised of markup tags that define the structure and components of a document. The tags are
used to tag text and integrate resources (such as images, sound, video, and animation) when you create a webpage.
hue
The property of a color that allows it to be classified by its name. For example, blue, green, and red are all hues.
hyperlink
An electronic link that provides access directly from one place in a document to another place in that document or to another document.
I
image map
A graphic in an HTML document that contains clickable areas that link to locations on the World Wide Web, to other HTML documents, or
to graphics.
imagesetter
A high-resolution device that creates film or film-based paper output used in the production of plates for printing presses.
intensity
Intensity is a measure of the brightness of the light pixels in a bitmap compared with the darker midtones and dark pixels. An increase in
intensity increases the vividness of whites while maintaining true darks.
interlaced video image
Interlaced video images take two passes to fill a screen, painting every other line in each pass. This can produce a flicker.
interlacing
In GIF images, a method that lets you display a web-based image on the screen at a low, blocky resolution. As the image data loads, the
image quality improves.
J
JavaScript
A scripting language used on the web to add interactive functions to HTML pages.
JPEG
A format for photographic images that offers compression with some loss of image quality. Because of their compression (up to 20 to 1)
and small file size, JPEG images are widely used in Internet publishing.
JPEG 2000
An improved version of the JPEG file format that features better compression and allows you to attach image information and assign a
different compression rate to an image area.
