Standard Print Quality: Color Gamut
In order to understand our results, you need to know how modern operating systems manage color. There is no printer (or monitor) in the world capable of reproducing all the colors we can see. On a computer, this problem is made more complicated since printers and monitors tend to have different strengths in color production. As a result, what you see on the screen is often different from what you print, and everything is different from the original picture that you took.
This is what professional photographers refer to as "gamut mismatch." If your monitor can't display all of the colors in a photo, you need to know which colors are out-of-gamut so that you don't incorrectly edit your picture. Operating systems like Windows 7 and OS X overcome this through a process called color management. The two major methods are known as perceptual and relative colorimetric rendering. Each places a different priority on how to render colors.
| Original Picture | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|---|
| Relative Colorimetric Rendering (mapping to 3-8) | 3 | 3 | 3 | 4 | 5 | 6 | 7 | 8 | 8 | 8 |
| Perceptual Colorimetric Rendering (mapping to 3-8) | 3 | 3.33 | 3.66 | 4 | 5 | 6 | 7 | 7.33 | 7.66 | 8 |
We'll use numbers instead of color hues because they're easier to understand. Say you have 10 shades of blue in a picture, 1 being the lightest and 10 being the darkest. If your printer can only print hues 3-8, you have to either toss out the other hues or change the color scale. Relative colorimetric rendering maps all the out of gamut colors to the extreme ends. This means that 3 represents any hue less than 3. Perceptual relies more on scaling. Instead of truncating color data, it maps on the same scale. Since the original picture had 10 shades of blue, it manipulates the extreme ends to make sure there are still 10 shades of blue.
Perceptual colorimetric rendering is vastly more complicated than relative, so don't assume that all of the middle hues go unmolested. The final result depends on the color management module (Adobe ACE, Microsoft ICM, and Apple ColorSync). In a nutshell, relative rendering destroys color information that cannot be displayed, while perceptual rendering compresses the information.
Neither rendering method is superior. Professional photographers have uses for each. However, on a day-to-day basis, you'll generally deal with perceptual rendering. That's how we are treating the color management of our paper samples. In order to see how each paper performs, we map the perceptual gamut (solid volume) in LAB space so that we can identify areas where the color gamut is mismatched. The wire form outline in each video represents the total gamut volume of AdobeRGB 1998.
HP’s Bright White performs the best out of all the printer papers, and Brother’s Multipurpose performs the worst.
Surprisingly, Dynex (Best Buy’s store brand) performs the second-best in terms of perceptual gamut volume. The difference is obvious once we look at profile slices. At 30% luminance, Dynex produces better magenta, blue, and cyan shadows. Dynex continues to hold a strong advantage up until about 60% luminance. We can clearly see a wider production of magenta, cyan, and yellow midtones, while the Bright White paper from Epson and HP both produce strong blue and cyan highlights.
