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发信人: killest (矛盾), 信区: Graphics
标  题: PHOTOSHOP(102)-Saving and Exporting
发信站: 紫丁香 (Fri May  8 17:55:21 1998), 转信

proof the image by printing this low-resolution
file from the destination application. If you want
to proof the color accurately, choose On (72 pix-els/
inch color); keep in mind, however, that this
option may substantially increase the file size. If
you抮e certain that you will print directly to film,
choose On (no composite PostScript).
Transparent Whites Select Transparent Whites to
make the white areas in an image appear transpar-ent.
This option is available only when saving a
Bitmap-mode image in Photoshop EPS format.
Saving files in JPEG format
When saving in JPEG format, you can specify an
image quality and compression level for the file. To
specify image quality, enter a value between 0 and
10 or choose an option for Quality; to specify the
amount of compression, drag the slider.A trade-off
exists between the image quality and the
amount of compression; an image compressed
using Maximum quality is less compressed (and
thus takes up more disk space) than an image
compressed using the Low quality option.
In addition, you can select a format option for the
JPEG file. To optimize the color quality of the
image, select Baseline Optimized. To save the file
as a progressive JPEG, select Progressive. This
option displays the image gradually as it is down-loaded
from a Web browser, using a series of scans
to show increasingly detailed versions of the entire
image until all of the data has finished download-ing.
However, progressive JPEG images require
more RAM for viewing and are not supported by
all Web browsers. When you select Progressive,
you can also specify the number of progressive
scans.
Exporting images
Adobe Photoshop includes plug-in modules
for creating GIF files for online display, exporting
paths to Adobe Illustrator, and saving Quick Edit
files (see 揙pening QuickEdit files� on page 57 and
揈xporting paths to Adobe Illustrator� on
page 324).
The GIF89a Export module lets you convert RGB
images to indexed-color GIF files and specify the
number of colors you want the file to have. In
addition, the command lets you designate trans-parent
areas in your GIF images for use in hyper-text
markup language (HTML) documents used
on the World Wide Web. Adobe Photoshop 4.0 can
open and save CompuServe � GIF files that are
either 8-bit indexed color or grayscale.
To use an export module:
Choose File > Export, and select an export format
or method from the submenu.
See the following sections for a discussion of the
GIF89a export module.
Exporting RGB images to GIF
When you export an RGB image to GIF, you can
use layers in Adobe Photoshop to define what
parts of the image you want to appear transparent.
The GIF89a export feature then lets you convert
CHAPTER 13 312
Saving and Exporting Images
the image to indexed color, choose a transparency
color for the Web browser, and save the image as a
GIF file.
To export an RGB image to GIF:
1 If you want to include only part of the RGB
image in your HTML document, select that part of
the image and feather it if desired. Copy the selec-tion
onto a new, transparent layer. Be sure to hide
any layers that you do not want to include in the
GIF file. For more information, see Chapter 11,
揢sing Layers.�
Original Selection copied to
transparent layer
2 Choose File > Export > GIF89a Export.
3 To display transparent areas of the image as a
solid color, do one of the following: To make transparent areas the same color as the
Web browser window background, leave the
Transparency Index Color box at the default color.
The default color is Netscape gray, which is 192 R,
192 G, and 192 B. To change the color used for displaying trans-parent
areas, click the Transparency Index Color
box, and choose a new color, as described on
page 225. Click OK.
4 For Palette, choose one of the following options: Exact to create a palette using the colors in the
image. This option is not dimmed (Macintosh) or
visible (Windows) only if the image contains 256
or fewer colors. Adaptive to create a palette using a representa-tive
sample of colors in the image. Use this option
for the best results if the Exact option is unavail-able.
When multiple images are displayed simulta-neously,
the Netscape 1.1 (or higher) browser
dynamically creates a color table using the adap-tive
palettes. System to create a color table using the
computer抯 built-in color palette. Note that the
System option may produce unexpected results
when the image is displayed on an 8-bit monitor
using a different built-in palette.
5 To select a custom palette that you have created
in Adobe Photoshop, click Load, and locate and
select a custom palette. Then click OK.
313
PREPARING IMAGES FOR ONLINE DISTRIBUTION When you distribute an image online, such as through electronic mail
or on a Web page, several factors affect the quality and speed of output, including your color calibration settings, the file
size and resolution, and the file format you use for the final images.
1. Adjust the Printing Inks Setup
settings to ensure color consistency
between applications. (Chapter 5,
page 103).
2. Create and composite the image in
Adobe Photoshop, and apply color
correction to the image. (Chapters
6�12).
3. Determine the display dimensions
for the on-screen image, based on the
monitor resolution and file size needed
for the image (Chapter 3, page 42).
4. Save the file in JPEG format or
export the file in GIF89a format,
depending on your display
requirements (page 327).
5. For the GIF89a Export module,
choose the number of colors and the
transparency color (pages 321
and 324).
6. Link the file to the HTML
document or convert the file to PDF
format (page 329).

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