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ADOBE PHOTOSHOP CS2
User Guide
OpenEXR format
OpenEXR (EXR) is a file format used by the visual effects industry for high dynamic range images. The film format
has high color fidelity and a dynamic range suitable for use in motion picture production. Developed by Industrial
Light and Magic, OpenEXR supports multiple lossless or lossy compression methods. An OpenEXR film can contain
an arbitrary number of channels, and the format supports both 16-bit and 32-bit images.
PCX
PCX format is commonly used by IBM PC-compatible computers. Most PC software supports version 5 of PCX
format. A standard VGA color palette is used with version 3 files, which do not support custom color palettes.
PCX format supports Bitmap, Grayscale, Indexed Color, and RGB color modes, and does not support alpha channels.
PCX supports the RLE compression method. Images can have a bit depth of 1, 4, 8, or 24.
Portable Document Format (PDF) is a flexible, cross-platform, cross-application file format. Based on the PostScript
imaging model, PDF files accurately display and preserve fonts, page layouts, and both vector and bitmap graphics.
In addition, PDF files can contain electronic document search and navigation features such as electronic links. PDF
supports 16-bits-per-channel images. Adobe Acrobat also has a Touch Up Object tool for minor editing of images in
a PDF. For more information about working with images in PDFs, see Acrobat Help.
Note:
The Touch Up Object tool is mainly for last-minute revisions to images and objects. It’s best to do image editing in
Photoshop before saving as PDF.
Photoshop and ImageReady recognize two types of PDF files: Photoshop PDF files and Generic PDF files. You can
open both types of PDF files; however, you can save images only to Photoshop PDF format.
Photoshop PDF files
Created using the Photoshop Save As command. Photoshop PDF files can contain only a
single image.
Photoshop PDF format supports all of the color modes (except Multichannel mode) and features that are supported
in standard Photoshop format. Photoshop PDF also supports JPEG and ZIP compression, except for Bitmap-mode
images, which use CCITT Group 4 compression.
Generic PDF files
Created using applications other than Photoshop, such as Adobe Acrobat and Adobe Illustrator.
They can contain multiple pages and images. When you open a Generic PDF file, Photoshop rasterizes the image.
PICT File
PICT format is used in Mac OS graphics and page-layout applications as an intermediary file format for transferring
images between applications. PICT format supports RGB images with a single alpha channel and Indexed Color,
Grayscale, and Bitmap mode images without alpha channels. PICT format is especially effective for compressing
images with large areas of solid color. This compression can be substantial for alpha channels with their large areas
of white and black.
When saving an RGB image in PICT format, you can choose either a 16-bit or 32-bit pixel resolution. For bitmap and
grayscale images, you can choose from 2, 4, or 8 bits per pixel. In Mac OS with QuickTime installed, four JPEG
compression options are available.
Note:
In ImageReady, PICT format is supported in Mac OS only.
