Beauty and the Beast -

When good design meets metamerism
by Brian J. Cowie, CEO CTI Paper Group, Inc.

Me-tam-e-whatta? What is this mythical-sounding beast? Simply put, "Metamerism," - pronounced:  - is the shifting or changing colors on one substance (paper) under different light sources. When the substance is paper, metamerism is a formidable foe capable of attacking the very integrity of your expertly designed printed piece.

Your chosen paper stock can dramatically change the color appearance of your projects when subjected to different light sources. Common light sources include office lighting, which is mostly fluorescent; home lighting, which is mostly incandescent; and the good old natural source of light, the sun. So all you need to do is keep your projects out of the light, right? Don't retreat to your shadowy hideaway just yet. This beast called metamerism can be tamed - if you know its secrets.

Beauty is in the eye of the Beholder
And subject to lighting conditions

Have you ever purchased something that was the perfect color in the store, and when you got home, the color was different? Say while shopping, under fluorescent lighting, you see a pair of stunningly rich forest green corduroys. You don't hesitate to buy them. Then while you're proudly wearing the new pants the next day, strutting like a peacock into the bright sunshine, the color suddenly shifts to drab olive brown. Aaaaahhhh! As a horrified scream escapes your lips, you wonder what happened.

About the author: Brian J. Cowie is the CEO and founder of CTI Paper Group. He has spent the last 17 years developing paper grades, building paper brands and building global paper distribution for the group. Established in 1989, CTI Paper Group is an industry leader in paper design and distribution. The company is headquartered in Sun Prairie, Wisconsin and has three divisions, CTI Paper USA, WorldWin Papers and The Paper Mill Store. In a previous career he was a general partner of a boutique money management firm, Hugo Securities and then he was self employed as an independent floor trader on both the Chicago Mercantile Exchange and the Chicago Board of Trade.

You've just witnessed the power of metamerism to transform colors. The pants didn't change. Only the source of light changed, in turn, how your eyes and everyone else's perceived the light waves reflecting off the pants. And that my friends is metamerism, and the resulting beastly-brown pants.

The beast rears its ugly head

Be it pants or paper, the colors can shift with very surprising and often unwelcome results. On any given project, you probably pay close attention to the element of color in your design and don't want color shift to occur. This is your meal-ticket after all. The havoc metamerism can wreak on corporate logos alone makes it a force to reckon with. Imagine Coca-Cola's red showing up as orange or IBM being referred to as "Big Chartreuse." None of the scenarios would be a welcome addition to any client relationship. When you present your client with a new logo, brochure or any project, you want to maintain the precise look and mood you so diligently created with colors you carefully selected.

The Nature of the Beast

Metamerism in paper is the result of using various dyes or colorants in the coloration process, without considering the effects of color shift under different light sources. Although any variance in colorant choice can lead to a small degree of metamerism, the most obvious examples of metamerism-causing colorants are optical brighteners. Optical brighteners are chemicals that absorb UV light and re-emit visible, blue-white light. They are used to make whites and colors brighter than they normally would be. By simply avoiding these chemicals in paper, metamerism can be minimized. But this can be a big issue for a paper manufacturer because so many colors (especially whites) have optical brighteners, and it is difficult to keep them out of the recycled stream of mill broke, trimmings and other mill paper waste, within the mill. Paper mills really need to make an effort to completely segregate their broke stream to avoid optical brighteners becoming mixed into their general fiber source, and not many do this consistently.

Don't feed the animals

The easiest way to become a victim of metamerism is by being caught unaware and unarmed. "So, how do I stave off this beast?" you ask. "How do I choose a paper with minimal metameric properties? Can I be assured that when I buy sky blue, it's sky blue in all light? Will the PMS color in my logo be the true PMS color in all lighting conditions?"

The best and easiest way to make these determinations is by testing the paper yourself. The process is easy to perform. After all you don't need a degree to know what color red you like.

Arm yourself with knowledge

Take a sheet(s) of the color(s) you're considering and perhaps a few sheets of different colored paper, which you can use as color reference points for your eye. If you're matching to another color, whether a logo color or the color of a plastic cup, take the item along on an "alternate light hunt." Place your paper samples and references next to each other for easy comparison. First, observe the colors from inside your office, which will most likely be under fluorescent lights. If you're color matching, determine which color matches the item you brought? (Sometimes it's helpful to have another person make the observation with you.) Then, use an outside light source for comparison, either outside of your building or inside from a large light-filled window away from other light sources, and see if any of the colors change. If matching, does the color you first chose still match your item under the different light source? Look at your samples in direct sunlight and diffused sunlight. If there is an incandescent light available, look under that light too.

This is perhaps the most practical and cheapest way to conduct your own test for metamerism. Another testing option is the Pantone Color Viewing Light Box.

It's really that easy. If any of the papers you tested show significant color shift, you will see it very plainly. If you observe no color shift from one light source to another, you can move forward with your paper selection with confidence. If it is only a subtle color change, you may find that to be acceptable for your project. If you see a significant color shift, you may want to consider seeking a similar colored paper from the same paper mill or seek out another paper supplier.

In some cases you can avoid the need to test all together. for example the CTI Paper Group offers a line of 144 non-metameric colors sold as "TPMS card stock." All of the card stock colors offered in this line are specifically designed to have stable color under all light sources. TPMS card stock is rendered non-metameric by rigorously avoiding optical brighteners in the manufacturing process (except in white of course!). Each production of TPMS card stock is tested in our labs to ensure minimal color shift.

Happily Ever After

Now that you understand metamerism and how to spot it before you go to press, there's no reason to fear it. You can eliminate or factor in the color shift of paper and let the beauty of your design shine through. You have tamed the beast.