ASK RICK

ask-rick_2Rick Michaud is the president and founder of the Graphic Group. In twenty plus years managing the print process, Rick has come across every print issue imaginable. He loves to share his experience with you. This is your chance to pick his brain. Ask a question or just browse the collected wisdom.

Cracking on the Spine?

Question: The cover of the brochure that my printer delivered has cracking on the spine, why did this happen?

Answer: Scoring is a part of the bindery process that will help prevent or reduce cracking when folding stock.

The specific stock you are using will determine the most effective scoring method. There are three ways to score your material.

A press score is achieved by placing a score rule (a thin piece of metal with an adhesive backing) directly on the impression cylinder of a press. It will leave an indented impression on the press sheet, creating a channel for folding. This is the most economical to achieve a score line, but does not always yield the best results.

A rotary score uses a wheel placed on the bindery equipment prior to folding as an in-line process. This will create an adequate score line, especially when folding with the grain of the paper.

A die score involves a separate production process in which a steel scoring rule is placed in a jig or imbedded in a piece of wood, clamped on a die cutting press and produced as an off-line process. The die score is usually used on a piece that has multiple score directions, such as a pocket folder. This process creates a much better score that stretches the paper fibers. The die score is the best method for reducing cracking…it is also the most costly process.

The graphic group will always recommend the best method for your project.

What is Digital Printing?

Question: Every printer seems to be selling a digital printing solution. The processes appear to be different. What do you consider “digital printing”.

Answer: Digital printing has a couple of very distinct characteristics. The first property is that toner, either liquid or particle, is used to produce the image on the page and the second is that the print engine can produce a different image on every page. Print solutions not meeting these criteria are often marketed as digital printing. There are a number of solutions out there from various sources that image plates directly on a press. Applying the label digital printing to them is misleading. They are really offset presses with direct imaging technology installed.

What is Gas Ghosting?

Question: I recently had a project delayed. The print rep said the delay was caused by gas ghosting. He never full explained the problem. What is gas ghosting?

Answer: Gas ghosting, also known as gloss ghosting, is the transfer of a printed image from the front of one sheet to the back of another. The transfer is caused by a chemical reaction when vapors from ink drying on one side of the press sheet interacts chemically with dry ink or paper coating on the other side of the sheet. Gas ghosting can also result when the ink drying on the second side is accelerated or retarded by fumes given off by ink on the first side. The problem is typically solved by changing the chemical properties of one of the variables in the process.

Why is My Gradient Banding?

Question: Why do gradients band when offset printed? I have a gradient in a project that prints fine to my office printer. When it goes to offset the gradient shows banding.

Answer: A gradient is the transition of one or more colors from dark to light. They become problematic when the color varies too little over too large a distance or when the gradient ends in less than 5 percent of a color. Gradients without sufficient variance between the light and dark color may appear banded when printed. Office printers have trouble imaging dot values in the single digits. To solve the problem, they artificially increase low screen values. This accounts for the gradient printing without banding to the office printer but banding when offset.

Why Does One 80# Cover Feel Thinner Than Another?

Question: I notice that some 80# cover stocks appear to feel heavier than others. If they are both the same weight, how do you account for the difference?

Answer: All 80# cover stock is not created equal. To accurately assess the bulk of any stock you need to know its caliper value. The caliper value is the thickness of a single sheet measured with a micrometer and reported in ml’s (thousandths of an inch). North American, European and Asian paper mills manufacture paper using slightly different processes and specifications. The finish of the coating will also affect the bulk of the paper. Dull coated sheets have greater bulk than gloss coated sheets. Matte coated sheets have greater bulk that both gloss or dull. If bulk is important on a particular print project be sure get the papers caliper value to understand its thickness relative to its weight.