5
8. Check the graininess more closely by zooming in to a 200% view of the top of the hammer. Just resize
the LiveView window to see the zoom pop-up menu, and then choose 200% (or use the Photoshop
keyboard shortcut Ctrl - or +/Command - or +). Switch back and forth between the Optimized and
Original views to compare them.
9. Close the image without saving it.
If you’re planning to look at the steps in the next section right away, don’t close this image. Just switch
to the Original tab and then you’re ready for the next section.
Compressing a Photographic Image
Choosing a file format for an image depends in large part on what type of image it is. As a rule, full-color
photographs look best with JPEG settings because this file format was designed for compressing photo-
graphs. Adobe ImageReady software can import photographic images in a variety of formats, including
native Photoshop format, TIFF, Photo CD
™
, and more. You can see a full list of these formats in “Seamless
File Support” later in this document.
Try it:
1. Choose File > Open > Hammer.psd.
2. Choose JPEG from the file format pop-up menu in the Optimize palette (if necessary, choose
Window > Show Optimize). You can see that the JPEG file format offers:
• a Quality slider control and pop-up menu to set the image quality level.
• the Optimized option, which generates slightly smaller JPEG files based on the newer version of the
JPEG standard.
• the Progressive option, which is equivalent to interlaced GIF files (a low-resolution image downloads
first, and then progressively more detail appears in several passes).
Choosing lower quality settings will compress the file more, but sometimes causes small visible distor-
tions, called artifacts, to appear.
3. Click the Optimized tab in the LiveView window so ImageReady generates the optimised version. Note
that the optimised file size is much smaller than it was with GIF settings applied.
4. Experiment with the different JPEG settings. Choose Maximum from the Quality pop-up menu. Note
that the file size jumps up a lot. Now try a much lower setting. For example, drag the Quality slider to 1
or 2. Note that the on-screen image quality doesn’t change much, but the file size becomes consider-
ably smaller. In a Web production environment, you would choose the lowest possible setting that
doesn’t degrade the image.
5. Close the image without saving it.
About Saving
In this reviewer’s guide, you
won’t be saving files. However, as
you work more closely with the
software, you should know the
following:
Choosing File > Save saves the
non-optimized file as a PSD file
that you can edit later.
Choosing File > Save Optimized
saves the compressed version.
Choosing File > Export > Export
Optimized lets you save the file
in different formats, such as PICT,
BMP, or TIFF.