Datasheet

16-Bit Color Display or High-Color 5-Bit Image File Each color channel (red, green, blue)
gets 5 bits of space to store its value, resulting in an image that can display a maximum of
32,768 colors. Each color channel has a limited range of shades, but still gives a nice color
image. You might notice the gradation in the different shades of each color, which can
result in color banding in the image. There is little use of these limited-color images in CG
work, though you will find them used in web pages to maximize efficiency.
8-Bit Image File This format is referred to as 24-bit color display or True Color, especially
in Microsoft Windows desktop settings. Each color channel is given 8 bits for a range of
256 shades of each red, green, and blue channel. A total of 16 million colors are available
to use in the image. This color depth gives the best color quality for an image and is widely
used in most animation applications. The human eye cannot see quite as many shades of
color as there are in a True Color image. Most of your renders from 3ds Max will be 24-bit
color files.
16-Bit Image File Used primarily in film work using such file types as TIFF16, this type of
image file holds 16 bits of information for each color channel, resulting in an astounding
number of color levels and ranges. Each file can exceed several megabytes even at low res-
olutions. These files are primarily used in the professional workplace and are more stan-
dard for film work because outputting CG to film can require high levels of color and
brightness range in the image.
Floating Point/32-Bit Image File Thirty-two-bit floating-point images are commonly used
in film production to give the utmost attention to color depth. Most computers are capable
of rendering a huge range of tones and colors, and 32-bit floating-point images capture
that range effectively. These files (such as EXR and HDR images) are not easy to work with
and require a lot of tweaking in compositing to output properly.
EXR (based on the OpenEXR format pioneered by Industrial Light and Magic for high-end
film work) and High Dynamic Range (HDR) images are usually in 32-bit float format and
are incredibly detailed in the range of contrast they store. You should not worry about
32-bit images and high dynamic ranges such as this until you have gained a good amount
of experience with lighting and rendering.
Color Channels
As mentioned, each image file holds the color information in channels. All color images
have a red, green, and blue color channel. Each channel is a measurement of the amount
of red, green, or blue in areas of the image. A fourth channel, called the alpha channel, is
used as a transparency channel. This channel, also know as the matte channel, defines
which portions of the image are transparent or opaque. Not all image files have alpha
channels.
18 ■ chapter 1: Basic Concepts
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