24" LCD Round-Up: Acer S242HL, Dell U2412M, And Samsung T24A550

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Another batch of monitors just landed. This time, we're sampling 24" screens. If 27" is too big (and too expensive), and 23" is too small, this round-up is just what you need. We put three screens through the usual paces to find a definitive winner.

Black And White Uniformity, Viewing Angles

Another measurable quality of panel performance is brightness uniformity. Most manufacturers calibrate displays based on the center point of the screen. However, every area of the screen behaves differently. Sometimes you can get better performance in one specific region. As a result, we add a nine-point black and white luminance test to measure the performance of each monitor's panel.

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Acer S242HL bid
White Luminance cd/m^2
168.0450194.6798186.0228
166.9632192.4567173.1384
181.5509193.0398193.6341
Black Luminance cd/m^2
0.81341.00601.0290
0.87041.06591.0368
1.04071.07531.0571

The S242HL bid suffers from poor backlight uniformity. For whites, we achieve ~190 cd/m2 towards the center of the screen. But as we move further away, luminosity falls off, causing a banding effect. The upper left-hand corner produces a slightly deeper black, which throws off black uniformity to a small degree.

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Dell UltraSharp U2412M
White Luminance cd/m^2
159.7259177.4599162.5423
165.5319202.4358172.7532
168.5267175.4136173.3799
Black Luminance cd/m^2
0.10230.15660.3612
0.13090.20310.1105
0.40350.14420.1619

Black luminance is scattered on the U2412M, though the problem is barely noticeable thanks to deep black production. In our opinion, white luminance is more of an issue. Dead center, we're able to achieve 200 cd/m2, but luminance falls off as we move our spectrophotometer further away.

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Samsung SyncMaster T24A550/T24A350
White Luminance cd/m^2
124.7582146.5855129.2932
130.5615154.1653126.5797
135.0890149.5426140.1892
Black Luminance cd/m^2
0.29140.41610.2766
0.34290.34400.3071
0.33310.24390.2943

As we already mentioned, we had to settle for a lower 150 cd/m2 calibration on the T24A550 because the panel's backlight isn't of sufficient quality to hit 200 cd/m2.

At this lower calibration setting, Samsung offers up decent white uniformity, but we still see very strong luminance towards the center of the screen. Viewing a pure white background or an image with a bright color palate, the problem is quite evident.

Black uniformity is a bit more mixed. There's a strong tendency towards deep black production near the bottom edge of the screen, which skews perception to a small degree.