4K TV Reviews

Full-on/Full-off Contrast Ratio: Unmeasurable

The measurements here were made using CalMAN software from SpectraCal, together with the Photo Research PR-650 and Klein K-10A color meters, and the AVLab TPG UHD pattern generator from DVDO. All the results shown here were for 1080p, standard dynamic range, upconverted by the set to 4K (3840 x 2160).

With a full-field black test pattern on the screen, the Samsung’s full-array backlighting shuts down completely in any setting of the Smart LED local dimming control (even Off). With pause engaged on the Samsung UBD-K9500 Ultra HD Blu-ray player (which puts pause information across the top of the screen—slightly different than the pause bug on the Oppo BDP-105D I normally use for such tests), and with Smart LED on Low, the black level at center screen measured 0.001 ft-L. At a peak white level of 31.05 ft-L, this produced a full-on/full-off contrast ratio of 31,050:1. With Smart LED off and the same pause indications displayed, the black level measured 0.006 ft-L, for a full-on/full-off contrast ratio of 5,175:1.

With a 1080p input and standard dynamic range, the set was calibrated in the Movie Picture Mode. With the set’s Color Tone at Warm2, the highest pre-calibration Delta E was 2.21 at 50% bright- ness (50 IRE). No other level from 20% to 100% exceeded 1.95. After calibration, using the 2-point White Balance controls, the deviations were greatest from 40% to 70%. The maximum grayscale Delta E from 20% to 100% was 1.81 at 70%; the next highest was 1.48 at 60%. While these values were low enough to be visually inconsequential, attempts to improve them further using the 70% 10-point White Balance control made no difference; the control didn’t change anything. Nor did using the 60% and 80% controls to make a change in the 70% level (in the event that the percentage on the 10-point level controls didn’t line up precisely with the actual 70% level).

(Delta E is a figure of merit indicating how closely a display adheres to the HD color standard. Experts generally agree that at levels below 3 to 4, the result is visibly indistinguishable from perfect color tracking. Delta E may be used to characterize either white balance/grayscale, as above, or color, as below.)

In the Auto Color Space setting, the color gamut’s pre-calibration color Delta E was no higher than 3.21 (magenta) and 2.88 (red). After calibration in the Custom setting for Rec. 709, the highest color Delta E was 1.08 for blue.

With the Gamma control on –1, the post-calibration gamma from 20% to 90% was 2.37 at 20% to 2.21 at 90%.—TJN