|
6. Do Nothing
Believe it or not, thousands of professional DRAW users take this route.
They decide that they dont want to be bothered with the specter
of trapping, and they turn their film over to their print shops and hope
that the job comes out okay.
7. Tell DRAW to Trap for You
Since version 4, DRAW has offered an option called Auto-spreading, found
in the Separations page of the Print dialog. This option will spread,
or expand, certain objects by minuscule amounts, thus providing the tiny
overlap needed to prevent registration errors. Three criteria must be
met before Auto-spreading can be applied to an object: (1) it must contain
a uniform fill, (2) it must not be set to overprint via the pop-up menu,
and (3) it cannot have an outline.
Approach DRAWs Auto-spreading feature with caution. In theory,
its a credible tool, but many DRAW-using color professionals dont
trust it in actual implementation.
8. Do It Yourself
Weve already discussed how you can trap black text by having it
overprinted. With a bit of careful thought, you can use a technique based
on the overprint strategy to trap all the objects in your drawing. This
technique is called a trapping outline.
For example, in the discussion of the cube, you learned that the boundary
between the yellow face and the magenta face is a danger zone in the event
of a registration error. This is because there is a risk of a white streak
appearing if the yellow face is placed too low. The same issue applies
to the vertical boundary between the yellow and the blue face. A trapping
outline applied to that area is the answer. This thin, yellow rule will
nudge into and overprint on top of the magenta and blue faces. Here are
the steps to make it happen:
- 1. Apply a half-point yellow outline to the yellow
face. (Rule of thumb: When you have a choice, apply the trap to the
lighter-colored object.)
- 2. Click mouse Button 2 on the face, and choose
Overprint Outline.
When you apply an outline to an object, half of its thickness is on the
inside of the object, and half on the outside. In our example, therefore,
a half-point outline will encroach upon the magenta face by a quarter
of a pointa fairly typical trapping amount. With a normal outline,
the yellow would merely begin knocking out the magenta a quarter point
higher than otherwise, and you would have accomplished nothing. But to
apply the trap, you set the outline to be overprinted, and thats
the key to the entire puzzle. In that quarter-point space, the magenta
will be laid down underneath the yellow, and both ink colors will be present
in that area. Now if a registration error causes the yellow face to be
placed too low, the magenta ink will still cover that area. You have set
a trap against registration errors, thanks to one little overprinting
outline. Now, youll need to repeat the process for every potential
trapping problem area in your drawing.
|
| NOTE One implication
of the trapping outline: it has added one-quarter point of thickness
to only one face of the cube. This will likely go unnoticed by many
of your audiencebut youll know its there. If it
bothers you, you can add a corresponding half-point outline to the
other two faces, in the name of consistency.
|
The other area in this drawing that needs to be trapped is the magenta
A and the yellow face of the cube. Once again, a trapping outline
is the solution, this time applied to the A: use the same color
as the character itself, set it for a half-point thickness, and designate
it to be overprinted. As Figure 27.13 shows, the outline will be placed
on top of the yellow ink, ensuring ink coverage all the way around the
A.
FIGURE
27.13 The trapping outline around this character
prevents a white streak in the event of registration errors.
Incidentally, Figure 27.13 is heavily exaggerated. First of all, the
outline color is supposed to be the same as the fill color (good for actual
trapping, bad for demonstrating same). Second, the actual outline is supposed
to be very small, not the bulky 3-point outline that we have applied here.
When you trap for real, the outline wont be seen because all you
are adding is a tiny outline colored the same as the object itself. The
thickness of the trapping outline will vary depending on the screen frequency
you use and the press registration. Check with your print shop for the
appropriate thickness of the trap for your projector better yet,
let the specialists at the print shop handle the necessary trapping.
How CorelDRAW Lies to
You
If you took a color print of your postage stamp and held it up next to
the same drawing on screen, how would the two compare? Would they look:
- (a) The same?
- (b) Close enough?
- (c) Quite different?
- (d) Ridiculously different?
If you did this comparison 100 times, its likely that the result
would be (a), the same, approximately zero percent of the time. Its
equally likely that the answer would be (d), ridiculously different, more
often than (b), close enough. In other words, forget about accuracy
when using your display monitor to view print colors. And now that
youve read this far in the chapter, you know why that is: you cant
expect an RGB deviceone thats made for transmitting red, green,
and blue rays of lightto be able to depict how light will reflect
off a surface filled with cyan, magenta, and yellow inks.
Hyperbole aside, there might be hope for your poor monitor yet. And the
timing is right, because color printing has never been more approachable.
The last two years have seen great strides in alternate methods (other
than conventional film-to-plate-to-press printing) for achieving color
output. Many service bureaus and quick-copy shops now offer high-end color
copiers. Connected to a Fiery RIP (raster image processor), they can directly
image your computer files in impressive, continuous-tone (photo-realistic)
color.
Todays desktop color printers cost less and produce much higher
quality work than their predecessors. Most are still being used for proofing
purposes, but even some inexpensive models can now be used for certain
commercial projects. It is amazing how well photographs and complex DRAW
objects reproduce on, say, a budget-priced Epson inkjet printer with the
right kind of paper loaded.
Color output is a far more common goal today for average DRAW users.
Its not only the graphics professionals who must confront the complex
world of color. Which brings us to the issue of Corels color management
systemoverhauled in DRAW 6, improved somewhat in DRAW 7 and 8, but
still not quite perfect. In fairness, though, is there such a thing as
perfect color matching? Not a chance, and DRAWs system is as good
as any otherbetter, perhaps, because of all of the device profiles
it supplies.
When Blue
Is Purple
The custom DRAW palette has a color called, simply, Blue. As viewed on
your monitor, Blue is an entirely apt nameit looks absolutely and
undeniably blue to all but the color blind. (Actually, our color-blind
lead author says that it looks blue to him, too.)
But what happens when this simple color is printed? The so-called color
Blue is produced by combining 100% cyan with 100% magenta, and unfortunately,
this will always look purple.
|
|