So what does the brightness rating mean? Brightness is measured by shining blue light waves on a sheet of paper and then calculating how much of the light is reflected back (versus being absorbed). The process and protocols for taking brightness measurements have been standardized to three different scales. Each brightness scale uses a different type of blue light and to date there is no accurate cross reference between scales.

The traditional North American scale is referred to as the GE/TAPPI scale. It returns brightness ratings up to 100. There are two foreign brightness scales that are starting to gain some popularity in the United States because their ratings go above 100. These alternative ratings are referred to as the ISO and the D65 scales.

Uninformed consumers mistakenly believe that the higher the brightness number the brighter the paper. It is easy to make this common mistake when comparing ratings from different scales. For example, a 104 brightness rating on a foreign scale might only rate a 92 bright when measured on the GE/TAPPI scale. It is kind of like saying 32 degrees Fahrenheit is warmer than 0 degrees Celsius… no, they are both the same temperature; freezing.

Some paper distributors are starting to insist on standardization. For example, United Stationers will display the GE/TAPPI rating within a light bulb icon in its general line catalog in addition to whatever the manufacturer may claim on its packaging. Staples has also standardized to the traditional North American GE/TAPPI scale. By standardizing, it allows consumers the ability to compare apples to apples and make an informed purchase decision.

So if consumers focus so much on a paper’s brightness, why is whiteness important? By whiteness, one is referring to the shade of white for a particular sheet. The human eye is capable of seeing far more differences in whiteness shades than degrees of brightness. That means whiteness is actually more important than brightness.

There are many different shades of white. All it takes is a trip to the paint swatch display at a hardware store to prove that. Since we can see more of the color spectrum than we can the brightness spectrum, we are actually reacting to a paper’s color more than we are its brightness. That means our preferences are based more on color than brightness. Put several different paper brands with the same brightness rating side-by-side, you’ll be amazed at the differences. You will also probably find one that you like more than the others.

Is there a measurement scale for whiteness? Yes, it is referred to as CIE L-a-b and it is a three dimensional measurement of the visible light spectrum. The “L” value represents the amount of white light reflection. The red-green spectrum is represented in the “a” value while “b” measures blue-yellow light. Paper manufacturers typically manipulate the “b” value so that paper has either a “blue-white” shade or a “yellow-white” shade.

Beyond setting consumer preferences, a paper’s shade is also important whenever color is applied to it. For color printing, shade absolutely makes a difference. For example, applying blue ink to a paper with a yellow-white shade tends to skew the representation with a greenish cast.

Probably the most important thing to know about whiteness shades is to understand the impression they make on consumers. When consumers are given a choice of papers with the same brightness ratings, but different shades, and they have a preference, they claim that their paper choice is “better.” The paper choices are identical in their quality, the only difference is their shade, but suddenly the paper a particular consumer chooses causes less paper jams, looks better, runs easier, etc.

So for anyone selling paper to consumers, take note of the importance of shade. Find paper with a shade that your consumer responds to. Their personal preference is as unique as they are, so no two consumers will typically have the same exact preferences. But once you identify what they like… sell it to them! This will likely result in your customer sticking to the paper they prefer and shopping around less on the basis of price alone.