The gamma curves are close to each other at the default settings but differ from the theoretical curve for gamma 2.2 which goes lower (it is black in the diagram). >From a practical point of view, it means that the L220x displays halftones lighter than they should be. This drawback can be corrected by calibration with a special tool or by increasing the gamma in the graphics card driver. The L220x itself doesn’t offer a gamma adjustment option.
The gamma curves do not change much at the reduced brightness and contrast. They are still higher than the theoretical curve. More importantly, the monitor is able to reproduce the entire range of halftones, without losing in darks or lights.
Now that I have begun to scrutinize the sRGB mode, I want to show you its gamma curves, too. Although the sRGB standard specifies a gamma of 2.2, the diagram shows the same discrepancy: the gamma curves of the L220x are higher than the theoretical one. In other words, the gamma value is lower than 2.2
The ThinkVision L220x is set up well in terms of color temperature. The difference between the levels of gray is small in everywhere except for the cold Bluish mode. And if you reduce the contrast setting from the default 85% to at least 75%, the difference in the Bluish mode gets small, too.
On the other hand, the absolute temperature values are high. The Reddish mode yields a color temperature of about 8000K and is going to look bluish rather than reddish. The sRGB isn’t any warmer although it should yield a color temperature of 6500K according to the sRGB standard.
Trying to achieve a warmer image from this monitor I reduced its contrast setting to 75%, set the color temperature mode at Custom and chose the following: Red=100, Green=89, Blue=87. The result is shown in the last column of the table. As you can see, it is close to the desired 6500K. So, if the L220x seems to produce an exceedingly cold picture, try to set it up like I did.
The table with the results of my brightness and contrast ratio measurements also had a Custom column that listed the values of those parameters at my color temperature settings. I published them to show you that I could achieve the desired result without sacrificing the monitor’s brightness. However, a brightness of 300 nits is too high for work, so you can reduce the contrast and brightness settings to your taste, as described in the previous section, having saved the above-mentioned color temperature setup.
To make sure the setup is correct, I will place dots corresponding to the different modes and levels of gray on a typical CIE diagram. The black curve on the diagram denotes all possible values which the human eye perceives as white. If the dot is higher than the curve, white has a green hue. If the dot is lower, white has a pink hue.
So, my manual setup is nearly ideal. The preset color temperature modes are but slightly shifted towards green. You can hardly notice it with an unaided eye.
The average nonuniformity of white brightness is 5.7% with a maximum of 25.1%. There is a dark spot in the top right corner (to remind you, what you can see above is not a photograph but a diagram built within the picture of a monitor). If the screen is all black, the right side is darker, too. There are no conspicuously bright spots and the results are quite satisfactory: an average nonuniformity of 3.5% with a maximum deflection of 17.9%.
The response time average is 6.8 milliseconds (GtG) with a maximum of only 11.2 milliseconds. You can play dynamic games on this monitor comfortably.
Of course, such a low response time is due to response time compensation. RTC technology can be accompanied with visual artifacts that show up as light or rainbow trails behind moving objects. This monitor is not free from them. The average level of RTC errors is 9.2% and the maximum error is 32%. These are normal results. You can spot RTC-provoked artifacts but they won’t be a big nuisance.