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General performance
Warm-up (5.89)
Warm-up time for the PX20 of 14 seconds yielded a moderate score compared to all printers tested, but it scored lowest of all compact printers tested. The other two dye sub printers tested, the Canon CP730 and the Sony FP90, came up to ready status in 11 and 7 seconds, respectively.
Power Usage (5.83)
The PX20 also scored the lowest in our power usage test. We use a watt meter to test the watts used by the printer in various modes, including off, ready, idle, and printing. While it did use less average watts while printing than the CP730 and the FP90, the Panasonic PX20 used more power while off and in ready mode than the other two compact dye sub printers. This brought its score down lower.
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Power Usage (watts)
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Off
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Idle
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Ready
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Printing
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Self-Cleaning
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HP Photosmart A440
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0
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n/a
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3
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8
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12
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Epson PictureMate 240
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0
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n/a
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4
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12
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12
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Canon Selphy CP730
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0
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n/a
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3
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56
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n/a
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Sony PictureStation FP90
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0
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n/a
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4
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55
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n/a
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Panasonic PX20
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1
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5
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6
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31.5
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n/a
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Photo Speed/Timing (3.66)
Because the dye sublimation printing process requires four passes of the paper through the paper path to lay down the three colors plus the clear overcoat, printing speeds are slower than most inkjet and laser printers. The Panasonic PX20 prints even slower than many other dye subs and all of the dye subs we’ve tested, especially when printing from memory cards. The PX20 produced only about half a page per minute (around 2 minutes per page) for both small (6 mb) and large (19 mb) file sizes.
Compared to two compact inkjet printers that have come through our labs, the PX20 scored in the middle. It was much slower than the Epson PM240 and slightly faster than the HP A440.
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Photo Print Speeds in Pages per Minute
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From Computer
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From CompactFlash
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Small file
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Large file
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Small file
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Large file
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Sony PictureStation FP90
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1.18
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1.06
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1.36
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1.12
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Epson PictureMate Snap
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1.40
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1.40
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1.36
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0.10
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Canon Selphy CP730
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0.83
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0.81
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0.98
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1.00
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Panasonic FX-PX20
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0.73
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0.57
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0.56
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0.48
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HP Photosmart A440
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0.61
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0.60
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n/a
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n/a
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Color Accuracy (2.15)
Dye sub printers are not known for their color accuracy. Their color reproduction is limited. This is reflected in the scores of our color accuracy test, which we perform using a digital version of the Gretag Macbeth Colorchecker chart, devised for us by Bror Hultgren of Image Integration. The chart is a grid of standardized color patches representing often photographed colors and tones, including skin tones, shy blue, foliage green, and a six-step tonal scale of white to gray. An example of this chart is displayed below.
We print the digital Colorchecker chart out using the test printer, and then we read the color values (a coordinate value of where the color falls within a given color space) using our spectrophotometer. These La*b* values, as they are known, are compared to the actual values of the color patches. The difference between the printed chart’s values and the actual values results in a color error for each patch. The average error is what we base our color accuracy score on.
The Panasonic KX-PX20 scored a very low 2.18, representing a mean color error of 10.01, the second highest color error of any printer yet tested, second only to a laser printer. The Canon CP730 and the Sony FP90 scored close to this, but both had a lower error value—8.61 and 9.75, respectively.
The individual error values usually give an indication that a printer’s representation of colors is skewed toward or away from a certain side of the color spectrum. Often greens or yellows are consistently off. In the case of the PX20, there seems to be no set pattern. For example, blue had one of the largest error values of about 15, while cyan had one of the lowest error values, at just over 2. White had a low error value, while the other gray tones had much larger errors. Dark skin tones also showed a large error value. Most values were at least above 9.
We also printed the chart using a custom-made profile (using the EyeOnePro), and this showed much less color error, only 5.72. The greatest error showed in the greens, most notably green and bluish green. The lowest error values showed in the gray scale. Skin tones also had low error values. However, since most users of this printer will not be creating their own profiles, this printer is scored based on the default settings. The custom profile illustrates that this printer is capable of greater color accuracy than is possible using the default settings.
Color Gamut (1.74)
Color gamut is the range of colors that a printer is capable of reproducing. We measure this value using Gamutvision, which graphically displays the printer’s color profiles in comparison to an existing standard. We use Adobe RGB, a color space that is well beyond what most compact printers are able to reproduce. However, since we at Printerinfo test the whole range of printers from these compact models through high-end, wide format printers, it’s more appropriate to use the more commonly used Adobe RGB standard.
Gamutvision also displays the numeric value for these profiles, based on the number of colors the printer can reproduce. The Adobe RGB space displays a constant 1,225,088 colors. High-end photo printers can produce within the 60th percentile of colors, while most mid-range printers lie within the 40th to 50th percentiles. Other compact photo printers tested, including the Canon CP730 and Sony FP90 dye sub printers, scored in the low 40th percentile.
Since no profiles were provided with Panasonic PX20 compact photo printer, we created our own using Gretag Macbeth’s color profiling equipment: the Eye-One Pro spectrophotometer and the Eye-One Match software. We do this for every printer we test and compare the gamuts for each profile. The PX20 yielded only 29 percent of the Adobe RGB space, a very poor showing. The chart below shows the AdobeRGB color space as the wire frame and the PX20 custom color profile as the solid color form in the center. The PX20 profile is lacking in every respect, falling far short in every color except whites and very light yellows and pinks.
Dmax (2.96)
Another measure of print quality is the density of the black tones that the printer is capable of printing. The deeper the black, the potentially wider tonal range the printer can reproduce. The ideal standard value for a very rich, deep black is 2.50. This vale is known as Dmax. Many high-end photo printers can usually attain a Dmax value around 2.30.
Unfortunately, the Panasonic PX20’s Dmax value was one of the poorest we’ve seen—1.56. The other dye sub printer’s we’ve tested scored much higher. The Canon CP730 achieved a Dmax of 2.01, while the Sony FP90 produced an impressive 2.30, very high for a compact photo printer. The PX20’s score was somewhat comparable to a low-end inkjet printer by HP, the A440, which produced a Dmax of only 1.71.
Monochrome (4.00)
The PX20’s low Dmax score is certainly a reflection of its black-and-white printing performance. Our test print showed a very washed out and muddy print, with very limited definition and contrast, and a poor tonal range. The blacks clearly do not pop as much as is seen in the original image or prints made with other printers, leaving the print with a washed-out appearance. We would have liked to show a scan of the print here to illustrate our point, but unfortunately, the scan degraded the quality of the image enough to make a valid comparison to the original unfair.
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