Adobe ADBCD17648MC Manuale Utente

USING PHOTOSHOP ELEMENTS 8
Optimizing for the web

Use hard-edged transparency when you don’t know the background color of a web page, or when the web page 
background contains a texture or pattern. However, keep in mind that hard-edged transparency can cause jagged 
edges in the image.

Open or create an image that contains transparency, and choose File

  > Save For Web. 

In the Save For Web dialog box, select GIF or PNG-8 as the optimization format.

Select Transparency.

Select None from the Matte menu.

Although the JPEG format does not support transparency, you can specify a matte color to simulate the appearance of 
transparency in the original image. The matte color fills fully transparent pixels and blends with partially transparent 
pixels. When you place the JPEG on a web page with a background that matches the matte color, the image appears to 
blend with the background.

Open or create an image that contains transparency, and choose File

  > Save For Web. 

In the Save For Web dialog box, select JPEG as the optimization format.

Select a color from the Matte menu: None, Eyedropper Color (to use the color in the eyedropper sample box), 
White, Black, or Other (to select a color using the Color Picker).

When you select None, white is used as the matte color.

Most web images are created by designers using 24-bit color displays (which display over 16 million colors), although 
some users view web pages on computers with 8-bit color displays (which display only 256 colors). As a result, web 
images often contain colors not available on some computers. Computers use a technique called dithering to simulate 
colors they can’t display. Dithering uses adjacent pixels of different colors to give the appearance of a third color. For 
example, a red color and a yellow color may dither in a mosaic pattern to produce the illusion of an orange color that 
the 8-bit color panel doesn’t contain.