Printing & Design Tips: February 2003, Issue #19

How to Produce Even, Heavy-Coverage Solids

Let's say you want to print a thick background of a color on a pocket folder. You want the solid to be rich and even. You want to make sure there are no streaks and no mottling. You don't want any uneven paper surface formation or coating to show through the ink and and mar the even color. What can you do?

First of all, discuss your goals early with your printer and choose a high-quality sheet on which to print your job.

Beyond this, you have several printing options to consider, all of which involve extra printing units and therefore extra cost. In some cases these solutions will also require drying time between printing certain colors.

  1. You can print your color initially using one press unit and then a second time using the same color carried in another press unit. This is called a "double hit."
  2. You can print a process build of your color (4 units) and then cover this ink with a PMS version of the same color (5th unit).
  3. You can print a tint of your color (30 percent black, for instance) and then hit the same area again with 100 percent of the color.
  4. You can initially paint the sheet (i.e., lay down a heavy ink coating) with opaque white. This seals the paper in the same way that varnish seals wood. After you have allowed the ink to dry, you can overprint the white with your solid PMS color.
  5. You can paint the sheet with your heavy-coverage color and then print over this solid with a varnish tinted with the same solid color.

Depending on the effect and overall level of quality you want, it may be worth the extra time and expense these options will require.

Avoiding Cracking When Printing Heavy-Coverage Solids

When running heavy solids across a fold, score the stock first to avoid cracking. Also, run and fold the sheet parallel with the grain if at all possible.

Remember also that UV coating tends to crack when crossing a fold, as in saddle stitching. The white of the paper could then easily show through the ink and UV coating.

Avoiding Ghosting When Printing Heavy-Coverage Solids

"Ghosting" is an unwanted condition that occurs when an image on a press sheet also appears faintly elsewhere on the same press sheet. It is due to ink starvation: a shift back and forth from heavy ink coverage to light ink coverage back to heavy ink coverage. For example, surrounding a photograph on four sides with a heavy-coverage solid color might create such an effect. In such an example, you might see a faint image from within the photograph repeated in the solid color.

To avoid this:

  1. Share your design early with your printer. He may be able to position the page on the sheet, or impose the job, in a way that minimizes the chance of ghosting.
  2. Your printer may run the job on a larger sheet to allow for a take-off bar (also known as a ghost-bar) of the solid color. Such a bar helps equalize ink-laydown on the sheet by extending and evening out the printed area, thus avoiding ink starvation in any one place. As the name suggests, the take-off bar is trimmed away after printing.
  3. Your printer may run the job slightly tilted on the sheet. However, although this usually eliminates ghosting, it complicates trimming the job.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]