Adobe 13102498 - Photoshop CS3 - Mac User Manual page 472

PHOTOSHOP CS3 465
User Guide
You can use the Import command or the Open command to open a PICT resource. When saving a file as a PICT
resource, you can specify the resource ID and resource name. As with other PICT files, you also specify bit depth
and compression options.
Pixar format
The Pixar format is designed specifically for high-end graphics applications, such as those used for rendering three-
dimensional images and animation. Pixar format supports RGB and grayscale images with a single alpha channel.
PNG format
Developed as a patent-free alternative to GIF, Portable Network Graphics (PNG) format is used for lossless
compression and for display of images on the web. Unlike GIF, PNG supports 24-bit images and produces
background transparency without jagged edges; however, some web browsers do not support PNG images. PNG
format supports RGB, Indexed Color, Grayscale, and Bitmap mode images without alpha channels. PNG preserves
transparency in grayscale and RGB images.
Portable Bit Map format
The Portable Bit Map (PBM) file format, also known as Portable Bitmap Library and Portable Binary Map, supports
monochrome bitmaps (1 bit per pixel). The format can be used for lossless data transfer because many applications
support this format. You can even edit or create such files within a simple text editor.
The Portable Bit Map format serves as the common language of a large family of bitmap conversion filters including
Portable FloatMap (PFM), Portable Graymap (PGM), Portable Pixmap (PPM), and Portable Anymap (PNM). While
the PBM file format stores monochrome bitmaps, PGM additionally stores grayscale bitmaps, and PPM can also
store color bitmaps. PNM is not a different file format in itself, but a PNM file can hold PBM, PGM, or PPN files.
PFM is a floating-point image format that can be used for 32-bits-per-channel HDR files.
Radiance format
Radiance (HDR) is a 32-bits-per-channel file format used for high dynamic range images. This format was originally
developed for the Radiance system, a professional tool for visualizing lighting in virtual environments. The file
format stores the quantity of light per pixel instead of just the colors to be displayed on-screen. The levels of
luminosity accommodated by the Radiance format are far higher than the 256 levels in 8-bits-per-channel image file
formats. Radiance (HDR) files are often used in 3D modeling.
Scitex CT
Scitex Continuous Tone (CT) format is used for high-end image processing on Scitex computers. Contact Creo to
obtain utilities for transferring files saved in Scitex CT format to a Scitex system. Scitex CT format supports CMYK,
RGB, and grayscale images and does not support alpha channels.
CMYK images saved in Scitex CT format often have extremely large file sizes. These files are generated for input
using a Scitex scanner. Images saved in Scitex CT format are printed to film using a Scitex rasterizing unit, which
produces separations using a patented Scitex halftoning system. This system produces very few moiré patterns and
is often demanded in professional color work—for example, ads in magazines.