Newer versions of Photoshop (since version 6) and most other programs no longer
require this hand-holding.
One interesting feature of TIFF is its capability to save files in any bits-per-pixel
depth. If your scanner supports 48-bit depth, you can scan at this bit depth and then
save the resulting (huge) file as a TIFF file that is completely portable.Photoshop File Format
The Photoshop PSD format is the native file format for Adobe Photoshop and
Photoshop Elements. This format is also available in most high-end Adobe products
as an export option. The PSD format can store layers, layer sets, paths, channels,
masks, and annotations seamlessly. This often results in large files, but provides the
tools you need during a large, complicated project.
File size for the PSD format has always been an issue; PSD files are large.
File sizes for the Photoshop format are similar to TIFF files with LZW compression.
Table 7.2 compares the file sizes of a single image saved in a variety of TIFF and PSD
formats.Table 7.2 File-Size Reduction Using Compression File Formats
Photoshop format (48-bit depth) 45.6MB
Photoshop format (24-bit depth) 22.8MB
TIFF with no compression (48-bit) 70.1MB
TIFF with LZW compression (48-bit) 55.1MB
TIFF with no compression (24-bit) 22.8MB
TIFF with LZW compression (24-bit) 17.9MB
TIFF with ZIP compression (24-bit) 15.2MB
TIFF with JPEG compression (quality: 0) 565KB
TIFF with JPEG compression (quality: 6) 1.4MB
TIFF with JPEG compression (quality: 12) 11.6MB
As you can see, the Photoshop format isn’t that much better than TIFF with LZW
compression. Nevertheless, when you’re halfway through a major project and need
to keep layers, channels, paths, and masks in perfect registration, the PSD format is
the only choice.CHAPTER 7 FILES AND FILE FORMATS 95