Adobe illustrator 10 Manuale Utente

3 Enter a screen-angle value (the angle of the dot from the true horizontal) for one or 
more channels:

For Grayscale images use only channel 1. 

For RGB images, use channels 1, 2, and 3, which correspond to the red, green, and blue 

channels. 

For CMYK images, use all four channels, which correspond to the cyan, magenta, yellow, 

and black channels. 

Click Defaults to return all the screen angles to their default values. 

4 Click OK.

Crystallize Clumps pixels into a solid color in a polygon shape.

Mezzotint Converts an image to a random pattern of black-and-white areas or of fully 
saturated colors in a color image. To use the filter, choose a dot pattern from the Type 
pop-up menu in the Mezzotint dialog box.

Pointillize Breaks up the color in an image into randomly placed dots, as in a pointillist 
painting, and uses the background color as a canvas area between the dots.

The Sharpen filter and effect focus blurry images by increasing the contrast of adjacent 
pixels.

Unsharp Mask Finds the areas in the image where significant color changes occur and 
sharpens them. Use the Unsharp Mask filter to adjust the contrast of edge detail and 
produce a lighter and darker line on each side of the edge, to emphasize the edge and 
create the illusion of a sharper image.

Filters or effects in the Sketch submenu add texture to images, often for a 3-D effect. 
The filters also are useful for creating a fine-arts or hand-drawn look. Many of the Sketch 
filters use the foreground and background color as they redraw the image.

Bas Relief Transforms an image to appear carved in low relief and lit to accent the surface 
variations. Dark areas of the image take on the foreground color, light colors use the back-
ground color.

Chalk & Charcoal Redraws an image’s highlights and midtones with a solid midtone gray 
background drawn in coarse chalk. Shadow areas are replaced with black diagonal 
charcoal lines. The charcoal is drawn in the foreground color, the chalk in background 
color.

Charcoal Redraws an image to create a posterized, smudged effect. Major edges are 
boldly drawn while midtones are sketched using a diagonal stroke. Charcoal is the 
foreground color, and the paper is the background color.

Chrome Treats the image as if it were a polished chrome surface. Highlights are high 
points and shadows are low points in the reflecting surface. After applying the filter, 
use the Levels dialog box to add more contrast to the image.