For an example of this effect, draw several overlapping objects with different colors. Set the transfer mode of the front object to Differ- ence (see “Selecting transfer modes,” page 20.375). Choose Layout > Display Options. On the Display dialog box, change the Mode from RGB to CMYK. Click OK to close the dialog box. To refresh the screen, press Command+K (Mac) or F5 (Windows). You will proba- bly see a significant change in colors when you switch from RGB to CMYK mode. To set the color mode for screen compositing 1 Choose Layout > Display Options. 2 Select Grayscale, RGB, or CMYK in the Mode menu on the Display dialog box. Be sure to choose RGB for effects that will dis- played in RGB colors. Choose CMYK if you are using CMYK col- ors in a document that will be printed with process colors. Transparency and printing You can use transparency effects to create stunning images and com- plex illustrations. As with any graphic effects, however, images that appear perfect on screen can cause problems or produce unexpected results when you print a document. This section discusses some issues you should keep in mind to help ensure that your documents print successfully. Canvas uses special techniques to print some transparency effects. Canvas can send an instruction to print an opaque rectangle, for example, to most printers. However, to print a transparent rectangle, Canvas usually converts the object to an image. This process is called rasterizing or rendering. Canvas then sends the image data to the printer. In the Print dialog box, you can select options for printing objects and colors. The options can affect the time required to print a document, and how well colors match among objects. See “Transparency Ren- dering” on page 10.115. Output resolution of transparency effects You can specify an output resolution for a transparent object. If you don’t specify the resolution for Canvas to use, it selects the resolution based on the following guidelines: Tip Select Grayscale from the menu to lessen the required memory if working on complex graphics or editing images. In Grayscale mode, your screen redraws fast- er than in CMYK or RGB.
Canvas 8 Help: SpriteLayer effects (23 of 24)                                                       Page #377