There are three common groups of white shades:Īs noted above, often the blue white shade is used for paper because it appears to be a “whiter” white than true white. Shade, on the other hand, does not take into account any light reflection instead, it represents the color of the paper. Indoor lighting, of course, will change how white the paper appears, and this will vary even more between fluorescent and incandescent bulbs. This standard is called CIE Whiteness and was developed by the French-based International Commission on Illumination (also abbreviated CIE). The most common whiteness measure, D65 illumination, represents outdoor daylight. Using the entire spectrum of visible light, paper with a very high whiteness number can appear to have a blue tint depending on what light source it is viewed under. So, there will generally be a consensus that the higher the whiteness rating (which also uses a 0-100 scale), the whiter the paper. Because of this, the whiteness measure is more in line with our visual perception. Whereas brightness measures the reflection of a very specific wavelength of light, whiteness measures the reflection of all wavelengths of light across the visible spectrum.
Specifically, the blue light used to measure brightness has a wavelength of 457 nanometers (nm). Because of this, two types of paper with the same brightness can visually appear very different, even though their “brightness” is the same. Using the specific blue light to measure this reflection ignores longer wavelengths, including green and red. In other words, 95 bright paper reflects more light than an 85 bright paper, therefore appearing brighter. Brightness is measured on a scale of 0 to 100 – the higher the number, the brighter the paper. Paper Brightnessīrightness measures the amount of reflectance of a specific wavelength of blue light. It should be noted that though paper brightness and whiteness are somewhat similar, they are not interchangeable. While it’s easy to have a general idea of what the terms brightness, whiteness and shade mean, there can be quite a bit of confusion as to their technical definitions and how they affect the appearance of your final product. However, they all play an important role in determining the look of your final product. Paper brightness, paper whiteness and shade are three of the most often misunderstood variables of paper choice in print projects.
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