► Note 131

See the Web Optimization Settings section of the color insert for samples of a few color tables for GIF and PNG-8 images.

TRY IT To manipulate the colors in a GIF or PNG-8 file, you need to first access the file's color table by performing one of the following:

• In Photoshop choose File I Save For Web. Click the Optimize tab and then select GIF or PNG-8 from the File Type menu on the right. Below that lies the color table.

• In ImageReady click the Optimize tab at the top of the image window and choose Windows I Color Table to display the Color Table palette.

Indicates color is locked and can't be removed

Selected color

Number of colors in paletti

Click to make all areas containing selected color transparent Click to make selected color web-safe

Indicates color is locked and can't be removed

Selected color

Number of colors in paletti

Click to make all areas

Click to access an additional menu of options

Indicates color is web-safe

Click to remove selected color from the table

Click to add a new color to the table

Click to lock selected color

Click to lock selected color

Click to access an additional menu of options

Indicates color is web-safe

Click to remove selected color from the table

Click to add a new color to the table

In either case, the color table is filled with the colors in the image, based on the current optimization settings. For example, if you specify there should be 32 colors in the image, there will be 32 colors in the color table. (The only exception is when the program sees that there are fewer than 32 colors actually used in the image, in which case it will only include the colors actually used in the image in the color table.)

Likewise, if you specify that 50 percent of the colors in a color table with 32 colors should be web-safe, the program forces 16 colors into the web-safe palette. You can recognize a web-safe color in the color table because it has a small white circle in the center of it.

To further customize the color table, perform any of the following:

• Change the display of the color table Click the small triangle in the upper-right corner of the table and select from one of the different sorting order options: Unsorted, Sort By Hue, Sort By Luminance, or Sort By Popularity.

• Add a new color to the color table First, make sure there are no colors currently selected in the color table (choose Deselect All Colors from the Color Table palette menu). Then, use the Eyedropper tool to place the color you want to add in the color selection box (in Photoshop's Save For Web dialog box) or the foreground color swatch in the toolbox (in ImageReady's toolbox). Click the New Color button in the Color Table palette to add the currently selected color. (If your color table is restricted to a certain number of colors, such as 128 or 32, the new color will share the space occupied by the color with the closest value to the new color.)

• Force an existing color to be web-safe Click once on the color to select it (from either the image itself or the color table) and click the Web Shift button in the Color Table palette. To force multiple colors to be web-safe, SHIFT-click the colors (if they are next to each other), or CTRL-click (Windows) or CMD-click (Mac) the colors (if they aren't next to each other) and click the Web Shift button. Click the Web Shift button again to reverse the process.

• Force all non-web-safe colors to be web-safe Click the triangle in the upper-right corner of the Color Table palette to access the palette menu and choose Select All Non-Web Safe Colors. Click the Web Shift button at the bottom of the Color Table palette. Alternatively, you can change the Web Snap setting in the Optimize window to 100 percent.

• Lock a color in the color table, and prevent it from being deleted even if you reduce the number of colors in the palette Click once on the color in the color table to select it and click the Lock button at the bottom of the Color Table palette. You can recognize a locked color in the color table because a small white square is displayed in its lower-right corner. To unlock a color, select it and click the Lock button again. (Note that locking a color in Photoshop or ImageReady doesn't guarantee a user will have that color in their system palette when they try to view the image.)

• Delete a color from the color table Select the color in the color table and click the Trash button at the bottom of the palette. After deleting a color, any areas of the image that contained the color change to the color in the palette closest in value to the deleted color.

QUICK TIP

In ImageReady click and hold on a color in the color table for a few seconds to see where that color is used in the optimized image. (The areas will be temporarily highlighted.)

Once you've completed manipulating the color table for an image, it may be helpful to save the color table for future use. You can do so by choosing Save Color Table from the Color Table palette menu. Give it an appropriate name (the file extension .act is automatically added) and save it in the Presets/Optimized Colors folder inside the Photoshop program folder. Then, whenever you need to, you can choose Load Color Table from the palette menu to load it.

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