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
dont 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.