Viewing Optimized Image Information; Previewing Browser Dither; To Preview Image Gamma At Different Values; To Adjust The Image Gamma - Adobe PHOTOSHOP CS2 User Manual

Viewing optimized image information

The annotation area below each image in the Save For Web dialog box provides optimization information. The
annotation for the original image shows the file name and file size. The annotation for the optimized image shows
the current optimization options, the size of the optimized file, and the estimated download time using the selected
modem speed. You can choose a modem speed in the Preview pop-up menu.

Previewing browser dither

If an image contains more colors than the monitor can display, the browser will dither, or approximate, the colors
that it cannot display by blending colors that it can.
To show or hide the preview of browser dither, choose Browser Dither from the Preview pop-up menu. A check mark
indicates that browser dithering is active. Activating Browser Dither does not affect final image output.

To preview image gamma at different values

The gamma value of a computer monitor affects how light or dark an image looks in a web browser. Because
Windows systems use a gamma of 2.2, images look darker on Windows than on Mac OS systems, which are normally
set to a gamma of 1.8. You can preview how your images will look on systems with different gamma values and make
gamma adjustments to the image to compensate. Activating a preview option does not affect final image output.
Choose one of the following options by using the Save For Web dialog box Preview pop-up menu (Photoshop) or
by choosing an option from the View > Preview menu (ImageReady).
Makes no adjustments to image gamma. Uncompensated Color is the default setting.
Uncompensated Color
Standard Windows Color
Standard Macintosh Color
Use Document Color Profile or Use Embedded Color Profile
color profile in a color-managed document.
In ImageReady, you can edit your image in one window and view the same image with a different gamma value in
a second window. Choose Window > Arrange > New Window For [File Name]. With the new window active, choose
View > Preview, and then choose a different gamma value than the one used in the first window.

To adjust the image gamma

In ImageReady, use this simple adjustment to change the image gamma. In Photoshop, preview the image gamma
you want to match, and then use the Levels command to make the image lighter or darker.
1 In ImageReady, choose Image > Adjustment >Gamma, and make sure Preview is selected.
2 Do one of the following:
Select Windows To Macintosh to adjust gamma for display in Mac OS.
•
Select Macintosh To Windows to adjust gamma for display in Windows.
•
• Drag the Gamma slider, or enter a value in the text box between 0.1 and 9.99. The Gamma slider measures the
amount of change from the current gamma value. (The slider does not indicate the actual gamma value.)
Note: Images created in Photoshop 5.0 or later use the Windows gamma value (2.2) by default and are at the correct
gamma for display in Windows with no adjustment.
Displays an adjustment based on the default Windows gamma.
Displays an adjustment based on the default Macintosh gamma.
Adjusts the gamma to match any attached document
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User Guide