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11. Choose View > Browser Dither again to check that the dither problem is gone. Then choose the View
Browser Dither command again to turn this feature off, and close the illustration file without saving it.
Simulating Browser Dither
If you’ve been performing the steps in this guide, you’ve now tested the View Browser Dither feature a few
times and have a feel for its usefulness. Now here’s a little more background information about why this
feature matters. Most designers work with 24-bit video display cards, so they tend to have a slightly skewed
view of how colours appear on-screen. Many of the people visiting Web sites, for example, still work with 8-
bit displays. Designers have worked around this problem by sticking to the Web-safe colour palette, but many
chafe at this restriction and want to start working with the richer colour set available from Adaptive or Per-
ceptual palettes. In the past, this meant having to switch to 8-bit display mode to check out every image.
Adobe ImageReady solves the problem by providing a Preview Browser Dither feature, so you can instantly
simulate browser dither in the LiveView window and make appropriate colour adjustments.
Animation and Other Web Features
While Adobe ImageReady is primarily focused on enhancing the Web production process, it includes a
number of features that nicely round out a Web designer’s toolkit. In particular, it offers elegant tools for
quickly creating animated GIF files and for generating client-side image maps. You can also preview your
graphics in your choice of Web browsers with complete ease, and you can check out how your image looks
as a tiled background.
Creating an Animated GIF File
Most programs that generate animated GIF files force you to compress individual images and then animate
them as frames. If you want to edit the animation, you have to go back to each affected frame, edit it, and
then rebuild the file.
ImageReady is different. It treats each image layer as a cel in the animation. As you construct an animation
in the Animation palette, it saves a snapshot of the settings for that layer rather than a block of pixels. Any
nondestructive changes you can make to a layer, such as moving it or setting its opacity, visibility, mode, and
stacking order, you can also make to each frame. On the other hand, permanent changes, such as painting
on a layer or applying filters, apply to all the frames that use that layer.
This approach to creating animated GIFs offers several benefits:
• You can edit animation frames easily. For example, you can click a frame in the Animation palette and
reposition any element (layer) in it because positioning is one of the nondestructive changes stored with
each frame.
• You can create compact files because you’re mainly storing layer settings, not pixel data.
• You can store your animation files as Photoshop files that you can save, open, and edit easily.
• You can automatically generate frames in between two specified frames, a process called tweening.
Changes in position or opacity between the two frames are automatically varied in the new frames.
• You can make changes to a layer—such as swapping out a different element or changing its colour—and
automatically update any frame that uses this layer.
• You can review and tweak the compression settings for animated GIF files in the LiveView window with
the same ease as you would preview still images.
When you’re ready to output the animated GIF, ImageReady produces optimal image sizes by analysing
frame differences and only including changed areas. It also prevents flickering—a common animated GIF
problem—by enforcing consistency between frames.
The innovative Animation palette in ImageReady