Images on the Web
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Images are an essential part of any web page design.
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Images convey color and style and content
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They offer a means for navigation
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They also carry the company brand
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28.8 Kpbs modem is considered standard dial up connection.
Keep this in mind.
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If you are design for an intranet, this won't be a factor.
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If youare designing for a public audience, never slight standard
connection speed.
Digital Imaging Concepts
Pixels ––"picture element".
The smallest unit displayed on a computer screen.
Color depth––pixels provide color
information measured in bits. Ex. 4 bits of grayscale information
tranlates into 16 shades of gray. Eight bits of color information
translates into 256 colors. High bit values =increased color definition
and higher file sizes.
Image resolution––How precisely your
image is displayed on the screen. It relies on how many pixels are
dispplayed in your compter screen's height and width. Higher resolution=sharper,
clearer images. Standard screen display is 640x480, or 72 dots per
inch(dpi). For a mass audience use this setting.
Palettes––An 8 bit color display can
show millions of colors , but only 256 at one time. Those colors
are maintained in a system palette. The web is restricted to the
use of 256 colors only. They are what is known as a web safe palette.
Dithering––scattering of colored pixels
to make it appear as if there are additional colors in a limited
palette.
Bitmam vs vector graphics
Bitmap––An image based on a series
of little sqaures placed side by side. Each square contains a color
value that relates to the overall image. Enlarging bitmaps reveals
the roughness of the edges.
Vector––Images that are stoed in a
mathematical formula which is interpreted and displayed. Vector
images are much smaller in file size and scale without showing rough
edges like bitmaps.
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