Removing halos

When you make the canvas color transparent on an image that was previously anti-aliased, the pixels from the anti-aliasing remain. Then when you export (or in some cases, save) the graphic and place it on a web page with a different background color, the perimeter pixels of the anti-aliased object may be apparent on the web page's background. These form a halo, which is especially noticeable on a dark background.

You can easily prevent halos in native Fireworks PNG files and in imported Photoshop files. For other file types such as GIF, however, you must remove the halo manually.

To prevent halos in native Fireworks PNG files and imported Photoshop files, do one of the following:

• Set the Canvas Color in the Property inspector or the Matte Color in the Optimize panel to the color of the target web page background.
• With the object you want to export selected, select Hard from the Edge pop-up menu in the Property inspector.

To remove a halo manually from a GIF or other graphic file:

1. With the file open in Fireworks, click the Preview, 2-Up, or 4-Up button at the upper left of the Document window. In 2-Up or 4-Up view, click a view other than the original.
2. In the Optimize panel, select Index Transparency from the Transparency pop-up menu.
3. Click the Add Color to Transparency button and click a pixel in the halo.

   All pixels of the same color are removed in the preview.

4. If the halo is still there, repeat step 3 until the halo is gone.