Printing and Design Tips: November 2015, Issue #172

What is "Kiss Cutting"?

When you print labels, you must be able to easily peel the label off the backing sheet. Let's say you have a series of round stickers on a roll, and you want to remove the label without needing to cut out the paper around the label. Or let's say you have perforations between “peel and stick” (or self-adhesive) rectangular labels, and you want to easily remove the scrap litho paper from around the rectangular label.

In either case, “kiss cutting” the outer litho paper without damaging the liner behind the label can be very useful. To make this die cut, the printer uses a steel die on either a letterpress or a flexographic press. If the pattern of the die cut is too intricate, though, a controlled laser can be used to kiss cut the paper.

Consider this option the next time you buy litho labels.

What are Piggyback Labels?

In many cases when it's time to renew your subscription to a print magazine, you will receive an outer paper wrap around the magazine. This outer wrap will include a marketing pitch and a request for your address information. To make this process easier for you, the magazine subscription department often uses “piggyback labels” for addressing your publication. Instead of filling out your contact information by hand in ink, you just peel the label off the front of the magazine and stick it onto the subscription card.

These address labels are glued to the front of the magazine, as are other types of labels, but they are composed of both the label and an additional backing sheet. The backing sheet (which extends just slightly beyond your address label) is affixed to the magazine cover with a permanent glue, and the address label itself (a peel and stick label) is attached to the liner sheet.

Therefore, you can just peel the address label off the magazine cover without damaging the adhesive, and then reposition it on the reply card to extend or reinstate your magazine subscription. What could be easier than that?

Color is Based on Light

I once read that red paint in a closed paint can is really black, not red. And at night, when I look at red cars, they appear to be gray. Clearly light affects color.

The perception of color has both a physiological and a psychological dimension. Rods and cones in the eye actually do physically perceive color and relay this information to your brain, but on a psychological or subjective level, no two people will perceive color exactly the same.

To add to this confusion, if you cover one eye and then the other, you may see slightly different colors when looking at the same object (at least I do, when I look at the color red). Furthermore, researchers have proved that women see color better than men.

Clearly, a book could be written on the subject of color perception To further complicate matters, color perception depends on the surrounding light source (daylight, incandescent, or fluorescent light).

With all of these challenges, how can we possibly do an accurate press check to ensure that the colors of a printed piece are correct?

At present, the short answer to this question is that pressmen can print “to the numbers.” Using a spectrophotometer, pressmen can determine the exact color percentages that constitute a particular hue. (This is one of the main reasons that press checks have become less important than they were ten or twenty years ago.)

However, sometimes color has to be absolutely dead-on (in fashion photography, food imagery, and perhaps automotive marketing). In addition, the color has to be consistent throughout the run. In this case, we're really talking more about “critical color” than “pleasing color,” and for this level of quality a press check is often in order.

To ensure the consistent viewing of colors, printers provide viewing booths with 5000 degree Kelvin lights. This particular color “temperature” is comparable to sunlight. Unlike fluorescent light, 5000 degree Kelvin light does not add a yellowish or greenish color cast. Unlike incandescent light (the lights that we grew up with that are now called Edison bulbs), they don't add a red or orange cast to the colors you are viewing.

In addition, a printer will usually have 60 percent natural gray walls in the viewing booth to ensure neutral light reflectance and to avoid color shifts or casts.

Even if you never attend a press inspection, you can find these lights at hardware stores now. Just look for the Kelvin readings—the color of light. In addition to the brilliance of the light, expressed in “lumens,” you'll see on the carton a reference to the color of light, the “K” notation. More yellowish bulbs are noted as “soft white” or “warm white.” These have a Kelvin rating of approximately 2700K, depending on the manufacturer. Cool white lights have higher temperature ratings ranging from approximately 3600K to 5500K.

You may remember that printing paper often comes in yellow-white or blue-white shades as well. The yellowish shade highlights reds, yellows, and other warm tones, while the blue-white shade highlights cool tones such as blues and greens. (The blue-white shade may actually appear to be a brighter white and is therefore sometimes called “bright white” paper.) Many paper manufacturers may call the blue-white sheets “cool white” and the yellow white sheets “warm white” as well.

So what should you take away from all of this?

1. When you attend a press inspection, make sure you're viewing the printed sheets under 5000K light, ideally in a viewing booth with 60 percent gray walls.

2. Consider using blue-white (or daylight) bulbs in your design studio to view printed colors the most accurately, with the least color shift.

3. It doesn't hurt to check out a printed piece under incandescent light, fluorescent light, and natural light (sunlight is perfect for the third option). Make sure the colors look appealing under all three lighting conditions (although they will not look the same). After all, your reader may be using any one of these light sources.

4. It doesn't hurt to take someone with you on a press check. I used to bring an associate who is a woman, because I knew she could see color better than I. This is particularly helpful for high-profile, expensive print jobs that could be ruined if you miss any errors in color.

5. Keep in mind that the color of the paper as well as the color of light in the viewing area will affect the perceived color of your print job. Choose paper colors wisely, and ask for printed samples similar to your job. (For instance, some paper with a yellowish cast can make skin tones look jaundiced, although the same paper might be ideal for a beach scene.)

6. Remember that no matter what you do, people will see the colors a little differently from each other and from you. And they will respond to the color differently (different emotions, different associations). Even age, culture, and climate will make a difference.

[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.]