EXPERT ONLINE: Minimizing Overs; Vision Tests

Highlights from graphicartsonline.com's “Ask a Print Expert” blog, where Ray Prince tackles the latest inquiries from readers.

Question: Can digital prints color-match to regular offset prints? We came up short on a job and need 50 more copies, and we hate to go back on press.

Answer: Can you? Sure! How close you will match depends on your color management that is used in the plant as well as how well you maintain your digital print engine. Keep in mind that even if you went back to press (at a substantial cost), the color more than likely will not match perfectly.

Question: We are going back on press (again) to make up a shortfall of 550 pieces for a job. The cost is killing us because we have to do this on a regular basis. Not many customers will pay for overs any more. Suggestions?

Answer: Coming up short off press or out of the bindery is a significant problem. Too many is not as bad as not enough. Accurate counts are vital. These are normally obtained by weigh counting.

Going back to press is expensive, takes time, and may or may not match in color. Thus, many printers are using digital color or black-and-white units to make up the difference. This is cost effective and fast. In the case of books, there may be binding issues that will have to be thought out.

Question: My customers can't see color worth a darn. We are having trouble in the sheetfed area and in the digital press area. In many cases, we are asking our sales people to O.K. color when a customer cannot be in the plant.

Answer: Have you tested all employees for color blindness (illustration) and color acuity? There are tests for both items. Color vision does change, so employees should be tested every five years. If your firm is large, you may wish to purchase the tests; if your plant is small, you may find that a local printing association has them available.

Question: Why are we having such great difficulty with scratching on plates? Our pressmen have to hone plates on most jobs.

Answer: First, you need to rule out some of the root causes of scratches. Is the pressroom clean? Are the scratches straight lines or zig-zag lines? (A zig zag is usually a sign of hard particles, usually metal shavings from rags.) Are the plates coming from the plateroom interleaved with paper taped to the face of the plate? Some plate catchers on processors are not meant to stack plates—check yours.

Now, you are ready to look at handling in both the plateroom and pressroom. Are the plates being transported vertically? (They should be.)

There is such a thing as a scratch-resistant finisher. This product is made and sold by RBP Chemical Technology, Inc. of Milwaukee (800.558.0747, or www.rbpchemical.com). Some plate manufacturers question it, but I've found printers that love it—mainly those that have scratching problems.

ONLINE: e-mail questions to Ray at rprince@napl.org