you are sending documents to a commercial printer, ask about the appropriate halftone screen settings. Use printer’s default Select this option when you often print to desktop devices such as laser printers, and the default halftone screen frequency and angle are appropriate for your documents. Frequency To specify a halftone screen frequency, clear the “Use printer default” checkbox, and enter the frequency in lines per inch in the text box. A higher frequency requires a higher printer resolution to produce the same number of grayscale levels in printed halftones. Angle If you want to specify the angle of the screens used for half- toning, rather than use the printer’s default setting, clear the “Use printer default” checkbox, and enter the angle in the Angle checkbox. Display preferences Options on the Display tab let you customize the display. You can control transparency effects, display speed and display quality. Vector Quality The options in this pop-up menu affect the entire screen display in Canvas. Draft :  provides the fastest screen display by drawing vector objects less smoothly. Choosing this option can increase display speed by 300%.    Normal :  provides fast screen display and draws smooth vector objects. This is the recommended setting and is selected by default. Anti-aliased :  significantly smooths all objects on screen, including text and vector objects by anti-aliasing their edges. How- ever, this anti-aliasing slows the display compared to Draft or Nor- mal settings. The effect of the anti-aliased option is independent of the anti-aliased option on the Display tab. If either option is selected, text is anti-aliased and vice-versa. Interpolation When activated, this feature will significantly enhance the visual quality of scaled images. Interpolation takes place whenever an image needs to be reduced or downsampled. In other words, when- ever the number of pixels being displayed is less than the available number of pixels at the destination. An example of downsampling would be when a 300 ppi image is set to be displayed at 100%. Tip Anti-aliased is especially useful when you create screen shots or display slide shows on screen. Interpolation is a mathematical procedure which estimates values of a function at positions between listed or given values.
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