Adobe Photoshop CS3 - Manual (Page 473)

PHOTOSHOP CS3
User Guide
466
Targa
The Targa® (TGA) format is designed for systems using the Truevision® video board and is commonly supported by
MS-DOS color applications. Targa format supports 16-bit RGB images (5 bits x 3 color channels, plus one unused
bit), 24-bit RGB images (8 bits x 3 color channels), and 32-bit RGB images (8 bits x 3 color channels plus a single
8-bit alpha channel). Targa format also supports indexed-color and grayscale images without alpha channels. When
saving an RGB image in this format, you can choose a pixel depth and select RLE encoding to compress the image.
TIFF
Tagged-Image File Format (TIFF, TIF) is used to exchange files between applications and computer platforms. TIFF
is a flexible bitmap image format supported by virtually all paint, image-editing, and page-layout applications. Also,
virtually all desktop scanners can produce TIFF images. TIFF documents have a maximum file size of 4 GB.
Photoshop CS and later supports large documents saved in TIFF format. However, most other applications and older
versions of Photoshop do not support documents with file sizes greater than 2 GB.
TIFF format supports CMYK, RGB, Lab, Indexed Color, and Grayscale images with alpha channels and Bitmap
mode images without alpha channels. Photoshop can save layers in a TIFF file; however, if you open the file in
another application, only the flattened image is visible. Photoshop can also save annotations, transparency, and
multiresolution pyramid data in TIFF format.
In Photoshop, TIFF image files have a bit depth of 8, 16, or 32 bits per channel. You can save high dynamic range
images as 32-bits-per-channel TIFF files.
See also
“Save large documents” on page 442
WBMP format
WBMP format is the standard format for optimizing images for mobile devices, such as cell phones. WBMP supports
1-bit color, which means that WBMP images contain only black and white pixels.
Metadata and annotations
About metadata
Metadata is a set of standardized information about a file, such as author name, resolution, color space, copyright,
and keywords applied to it. For example, most digital cameras attach some basic information to an image file, such
as height, width, file format, and time the image was taken. You can use metadata to streamline your workflow and
organize your files.
About the XMP standard
Metadata information is stored using the Extensible Metadata Platform (XMP) standard, on which Adobe Bridge,
Adobe Illustrator, Adobe InDesign, and Adobe Photoshop are built. Adjustments made to images with Photoshop®
Camera Raw are stored as XMP metadata. XMP is built on XML, and in most cases the metadata is stored in the file.
If it isn’t possible to store the information in the file, metadata is stored in a separate file called a sidecar file. XMP
facilitates the exchange of metadata between Adobe applications and across publishing workflows. For example, you
can save metadata from one file as a template, and then import the metadata into other files.