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Return to the August 2009 issue of the SMS Register.
Designing your way out of trouble
It can be incredibly frustrating.
A particular page design may look great in your mind’s eye, even better on-screen and absolutely phenomenal in the proof. But when it’s printed, despite the press crew’s best efforts, it’s another story altogether.
The truth is that good design can’t occur in a vacuum; it needs to take into account the parameters imposed by the medium in which it is to be executed. There are things you can do in a sheetfed environment that you simply can’t do on a web press.
Pick up virtually any web-printed magazine from any newsstand and you’ll see examples of mechanical ghosting. Inherent to web presses — and exacerbated by the design or layout of the printed form — mechanical ghosting occurs when a large amount of ink printed in one area affects the ink density of another area.
Technically, mechanical ghosting occurs when the rollers that distribute ink in a press can’t replenish the depleted ink fast enough, effectively starving the plate of ink in some areas and causing a visible difference in coverage. A classic example of this appears at right.
Here, the image has a square border made up of solids or heavy screens. Unfortunately, the sides of the border are not as dark as the top and bottom because the vertical sections require far more ink to be supplied by the rollers in the printing units than do the top and bottom sections. The long borders strip the ink from the rollers faster than the printing unit can replenish it — with the result that the needed density can’t be maintained.
This problem can also be seen in the example at left, where the vertical edge of the green border is starving the rollers in the cyan unit and affecting both a section of the teal horizontal band immediately below and the purple band on the page running in-line with it. Unfortunately, proofs don’t show either of these problems.
The best solution is usually to modify your page design or — at minimum — ensure that problematic designs will not run in-line with one another. Fortunately, once this problem is understood, it’s relatively easy to predict where mechanical ghosting might occur. Using lighter screens, avoiding square-shaped tint panels and boxy designs, moving any dividing line off the perpendicular and making use of smaller-sized designs also help minimize the problem.
In-Line Compromise
Like ghosting, this issue is inherent in the printing process and is greatly influenced by page layout and design. It occurs when two printed images are imposed directly “in line” with one another in the direction in which the paper travels through the press and both feature the same color, one with much greater intensity.
A classic example is the case of a full-page advertisement showing a bright red automobile on one page, and another advertisement with a prominent blue sky on the page running in-line with it. Because the press requires a huge amount of magenta ink to get the correct density for the red car, so much ink must be applied to the rollers of the printing unit that the smaller, less-dense magenta dots in the blue sky become denser than they should be. The result is a bright red car on one page and a purple — rather than blue — sky on the other page.
This is a problem you’ll never see in a proof. It doesn’t show up until the job is on press, and at that point press crews are limited in their ability to solve it. Their only recourse is to compromise, reducing the amount of magenta ink to make the sky less purple and the car a less-vivid red. Unfortunately, they’re not in the best position to make this kind of subjective decision.
Once again, the design and layout of the magazine are the most influential factors in this problem. But you can always ask your account manager for guidance; if you know your page count, the AM can not only press-plan the job in advance and create a proof to show which pages will run in-line with one another, but can specifically check on any critical or problem pages and alert you to potential conflicts.
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Return to the August 2009 issue of the SMS Register.
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