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Photo Speed / Timing (45.95)
The Oki C6000n’s 4-by-6-inch photo printing speeds were off the charts, at 16 pages per minute, or 3.75 seconds per page. Letter-sized (8.5-by-11) images printed at he same rate. These scores were much better than the other color laser printer we’ve tested, the HP Color Laserjet 3600n. As with the document printing speeds, this is a very small sample size, so we will be better able to contextualize these scores once we have tested more laser printers.
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Photo Print Speeds in Pages Per Minute (ppm)
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4x6
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8.5 x 11
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sml
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lge
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sml
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lge
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Oki C6000n
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16
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16
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15
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16
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HP Color Laserjet 3600n
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2.89
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2.89
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4.9
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5.0
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Color Accuracy (2.56)
We test color accuracy by printing out a digital version of the 24-square Gretag Macbeth Colorchecker chart. A representation of the chart is shown below. Each of these squares has a color value associated with it, which is know as the La*b* value. (L refers to lightness or saturation, while a* and b* refer to the color’s position on the x and y axes, respectively, in an imaginary color space.) The numerical degree that the printed version of the chart deviates from the digital version is referred to as the Delta E mean color error. An average of those error values for each of the 24 squares gives us the basis for our score.
The Oki C6000n did not score well when it came to color accuracy using the printer’s Office Color setting set to sRGB in the Color tab of the driver. We printed with both the PCL driver and the PS driver, and found the PCL to give much better results. Prints were much more saturated.
The mean error was 8.39, compared to the HP 3600n’s mean error of 11.70. Many printers we’ve tested end up in the range of 6 to 9 mean error. Only the higher end photo printers have been able to achieve values as low as 1 or 2. However, a custom ICC profile can be created for any printer, including the Oki C6000n. Using this, the C6000’s mean color error was reduced to 4.12, a significant decrease.
Blues, oranges, and greens showed the most deviation from the ideal value, as did light skin and some gray tones, while white, cyan, and red had low error values.
Color Gamut (1.98)
The C6000n uses either a standard monitor profile or the sRGB color setting as a guide for printing. Since we could not measure the gamut of these, we used the custom ICC profile that we created with the EyeOne Match software and the EyeOne Pro spectrophotometer. Using this as a measure, the printer achieved a color gamut of 407,605 out of an ideal 1,225,088 colors, or 33 percent of the Adobe RGB color space. This is a pretty poor score, but still better than the HP 3600n, which was only able to represent about 22 percent of the Adobe space.
This profile and the color space are shown in the graph below. The Oki’s custom profile is represented by the color blob in the center of the wire frame—the Adobe RGB space. Noticeable are the large gaps in the green and yellows, as well as some of the blue part of the spectrum.
Dmax (3.74)
Of the three laser printers tested so far in our labs, the Oki C6000n yielded the highest dmax value of 1.83. The HP Color Laserjet 3600n, a comparably priced printer, yielded only 1.39, and the Lexmark X342n monochrome printer produced a dmax of 1.49. All three printers were tested on the same paper stock—Staples Color Laser paper (96 bright, 32 lb.) with the printers’ standard settings.
Dmax is a measure of the deepest black a printer can produce, with the ideal value being 2.50. Most home and office printers are unable to achieve that value, but some high-end photo printers have been known to reach 2.35. This value is important because it creates the dark level benchmark for the tones that a printer can produce, with the white of the paper setting the opposite benchmark.
Monochrome (5.00)
When printing a black-and-white image with the Oki C6000n, on the basic settings (automatic color management), the printer uses the three color toners to create the image. This results in a horrifically contrasty and oddly tinted print. However, when Grayscale is chosen in the Color tab, then the printer prints only with the black toner cartridge, resulting in a surprisingly good-looking image. Shadows and other dark tones were nowhere near as deep as an inkjet print, but otherwise there was good tonal separation and decent detail in the highlights.
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