CHAPTER 5: Document Settings

Bit Depth
Color Table
Transparent Color
Other Document Options

This chapter describes WebPainter's color capabilities that are achieved from the document settings. WebPainter provides a consistent, easy-to-use interface whether you're working in black and white or with millions of colors.

Document Settings Window

Bit Depth and Colors

The term bit depth refers to the number of bits used to encode color or gray-scale information for each dot in an image. In black-and-white images, each dot is either black or white, and so only 1-bit is necessary for each dot. If 4-bits are stored per dot, then 16 seperate code combinations, representing 16 colors, are possible for each dot. If 8-bits are stored per dot, then 256 separate code combinations, representing 256 colors, are possible for each dot. If 16-bits are stored per dot, then 32,768 seperate code combinations, representing 32,768 colors, are possible for each dot. And with a bit depth of 24, approximately 16.8 million color codes are available; therefore, an image document is simply a matrix of bit strings representing color codes for each dot.

WebPainter provides six document bit depths - 1-bit, 2-bit, 4-bit, 8-bit, 16-bit, and 24-bit. The following chart indicates the number of colors available with each bit depth.

Bit Depth Number of colors

1 1

2 2

4 16

8 256

16 65, 536

24 16 million (approx.)

Setting Document Bit Depth

The bit depth for new documents is specified in the Document Info dialog when a new document is created. The bit depth of the active document can be changed at any time in the Document dialog box located in the paint menu.

Bit Depth and Document Size

Bit depth is the number of bits assigned to each pixel to define color. It follows, then, that 24-bit documents can be significantly larger than 1-bit and 8-bit documents. This means that color graphics files can become very large, requiring a large amount of disk storage space, and slowing processing times considerably. We recommend that you give some thought to the expected use of your animations and set the document bit depth accordingly. If the image is to be used a low data rates of 14.4bps or 28.8bps, 24-bit color will probably create an animation that is too large. The following illustration indicates the document size of the same image when defined at bit depth of 1, 2, 4, 8 bits.

Illustration:

A 8 bit graphic

A 4 bit graphic

A 2 bit graphic

A 1 bit graphic

Color Table

Apple System Colors
The standard Mac graphics color palette.

Apple System Grayscales
The standard gray scale color palette.

Note: The above two options are available at default when a new document is created.

Windows Netscape Colors
The optimal 8-bit palette for running Netscape on Windows. If you want to reach the widest audience of Web/Internet users, most people will be able to view this mode the best.

Custom
This option is set by WebPainter itself when a custom color palette is used by an image. This option is selected under three situations:

1. After "Colors Used" is selected for an image that does not use all 256 colors of the standard Mac color palette.

2. After the user changes the system color or grayscale palette.

3. When an imported image uses a non-system color or grayscale palette.

Colors Used In Document
When this option is selected, only the colors used in an existing image are shown on the color selection palette.

Transparent Color

Transparent color is the color that cannot be selected by the Selection (Marquee, Magic Wand and Lasso) tools and allows the background image to show through to the foreground cel. White is the default transparent color. To select a transparent color click on the square located beside "Transparent Color" and drag cursor to the required color.

Bit Depth	Number of colors
1	1
2	2
4	16
8	256
16	65, 536
24	16 million (approx.)