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. It’s 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) isn’t 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 isn’t visible on screen. Without overprinting, the orange circle knocks out part of the gray circle. knockout Overprinted object
Canvas 8 Help: Working with objects (40 of 52)                                                      Page #284