Digital Image Formats - A Practical Guide to Video and Audio Compression - page 139

Table 6-6 Other Non-RGB Formats

Format Description

CMY Cyan, magenta and yellow. The blacks are not very dense and are often

called brown-black.

CMYK Cyan, magenta, and yellow with the K value representing an additional

black channel. This value must be subtracted from the CMY values to
achieve under-color removal.

GIF Compressed-image format using Lempel-Ziv-Welch (LZW) compression

originally developed for CompuServe. Unisys owns the patent.

HLS Hue lightness and saturation

HSV Hue saturation and value

JPEG Joint Photographic Experts Group still-image format. Uses DCT

transforms but no inter-frame computation.

JPEG-2000 A more recent version of the JPEG standard that allows for wavelet

compression of still images.

LAB Luma plus two color-difference values (chroma). The color-difference

values represent the yellow-blue axis and the magenta-green axis.

PDF Although not an image format itself, PDF files are being used

increasingly as image containers with other formats embedded inside them.
It is theoretically possible to convert between a movie file and a sequence of
PDF files and vice versa. Since Mac OS X uses PDF for the display-imaging
model, this will become more popular.

PICT The Apple Macintosh picture format, revised and extended over the

years to include compression.

Pixlet Pixlet compression was developed by Apple and shipped in QuickTime

6.4 for Mac OS X. This uses a still image-based wavelet compression in a
motion video container to provide compressed video with no observable
artifacts. The name is derived from the words Pixar and wavelet.

PNG Portable graphics format developed in response to the patent claim by

Unisys. It was intended to replace GIF images on the Internet.

TIFF Tagged image format originally codeveloped by Microsoft and Aldus

for the pre-press industry. Various versions have been developed since.

nance of a scene is mapped to the behavior of the human eye, and the range of available
brightness values for 8-bit and HDR are both shown on the same axis. In this case the word
luminance is the lighting and color science value and must not be confused with luma val-
ues discussed elsewhere.