Editing trap properties

At the end of this exercise, you should be able to perform the following tasks:

• Use default trapping parameters to trap a page containing vector objects.
• Edit traps for color, size, and line join style.

Note: We recommend that you print this procedure, and follow the steps using the opened drawing file:

1. Open EditProperties.pdf.
2. Start PDF Trap Editor.
3. On the Properties Editor toolbar, click the Trap Page button.
4. In the Trap Page dialog box, do not change any trap parameter settings.
5. Click the Trap Page button in the dialog box.
6. Check the trapped page.
   Why didn't the 7 in the second drawing get a trap?
   The color values for the 7 and its background are too close to need a trap. Select each item as an object and check its color formula in the Properties Editor.
7. Using the Trap Page dialog box, experiment with retrapping the page with different trap width settings.
8. Check the traps in the file. What trap width best suits this page. Why?
   Smaller trap widths are more suitable for commercial printing.
9. On the PDF Trap Editor action toolbar, click the Trap Page button. In the Trap Page dialog box, change the Trap Width setting back to the default 0.25 pt.
10. Check the traps for the first drawing in the file. Do some traps look too dark?
    Do the traps between objects Pantone 3268 and Pantone 676 look too dark?
    Between 42c60m0y12k and Pantone 676?
    Between 89c12m27y0k and Pantone 676?
    Between 60c0m70y0k and Pantone 676?
11. Select a trap or traps from the list above, and scale the trap color to your satisfaction by changing the trap's color separation values in the Properties Editor.
12. Select the circular object in the middle of the multicolored square. Change its status from knockout to overprint. What happens?
    The underlying objects/colors show through the object. When printed, the inks for the underlying objects are laid down, then the overprinting object is painted on top. Since the top color doesn't have enough density to obscure the underlying colors, the underlying colors bleed through.
13. In the third drawing, select the trap where the two rectangles meet, and check its shape. Now apply clipped chokes to the trap using the Properties Editor. What happens to the trap?
    The trap forms a continuation of the yellow shape, which is less noticeable if a misregistration occurs.
14. Select the trap between the blue triangle and its pink background, and change the default beveled line join to a miter.
15. Experiment with applying different miter limits. What do you see?
    A low miter limit produces a bevel on the trap join.
16. Close EditProperties.pdf without saving.