Setting print properties for objects
The Trap tab in the Object Specs palette lets you set overprinting and
trapping options for color separations. You can apply the settings to
selected objects by clicking Apply in the Object Specs palette.
Overprinting in color separations
When you output color separations in Canvas, you can specify that an
object should overprint, rather than knock out, objects behind it.
In color separations designed for commercial printing, a front object
usually knocks out a hole where it overlaps other objects. How-
ever, you can apply the Overprint Object option to an object to pre-
vent it from creating knockouts in objects behind it. This can
compensate for registration problems on some printing presses.
For example, if you draw a cyan circle on a yellow background, Can-
vas knocks the circle out of the background in color separations so
cyan and yellow do not mix in the circle. If you select the circle and
use the Overprint Object option, the circle will print over a solid yel-
low background, and the cyan in the circle will mix with the back-
ground yellow, resulting in a green circle.
The effect of the Overprint Object option is not visible on screen.
This effect is visible only in the printed output when you produce
color separations. You can verify the settings for a particular object
by viewing the Options tab in the Object Specs palette and then
selecting the object.
Color mixing as described in the previous example is not the primary
reason for overprinting. Its more common for designers to overprint
dark objects on lighter backgrounds as a way to prevent a gap from
appearing between the colors if the press registration (alignment)
isnt perfect.
To specify overprinting for objects
1
Select the vector or text objects to be overprinted.
2
Select the Overprint Object checkbox on the Trap tab in the
Object Specs palette.
3
Click Apply. The appearance of the selected objects does not
change on screen, but the objects will be overprinted in color sepa-
rations.
Overprinting produces a color
mixture where the orange circle
overlaps the gray circle. This
effect isnt visible on screen.
Without overprinting, the
orange circle knocks out part of
the gray circle.
knockout
Overprinted object