Author Topic: LG 27UL550 Review: Matte 3840x2160 LG AH-IPS with AMD Free-Sync  (Read 6938 times)

NCX

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Beautiful But In Need Of A Tune-Up
« on: May 24, 2019, 08:47:09 pm »
Preset Color Accuracy

DSC_0039 by Dr NCX, on Flickr

The preset color accuracy offered by the 27UL550 is accurate and vibrant enough to not suffer from obvious flaws, looks very similar to the higher end 4K panel in my calibrated ViewSonic VP2780-4K, and the 27UL550 completely covers the SDR (HDTV/REC 709 & sRGB) color spaces.  The 27UL550 does slightly over-saturates greens, oranges, reds and yellows (HCFR color space measurements), but this is normal for mid-range and non-professionally oriented 2560x1440-38420x2160 AHVA, IPS, PLS and VA panels; minor over-saturation is preferable to under-saturation for multiple reasons I will not explain here. 

The 27UL550 suffers from slight gamma flaws and a minor preset blue tint out-of-the-box, but it can be slightly reduced by switching to the SMPTE-C Picture mode.  The gamma flaws result in light greys and colors not being are not as dark as they should be in the 50-100% white range (see my HCFR gamma measurements here or below), but these flaws are only noticeable when compared to calibrated monitor, as well as slightly less prevalent when set to the SMPTE-C Picture Mode.  The preset blue tint is replaced with a lighter and less obvious preset purple tint when set to the more accurate SMPTE-C mode, but both the preset Standard mode and the SMPTE-C mode are accurate enough for work which requires color accuracy, as well as offer nearly equally beautiful and vibrant image quality compared to the higher end and calibrated ViewSonic VP2780-4K.

The 27UL550 can accept an HDR 10 signal, but it does not have

+10 bit panel
+1,000cdm/2 brightness
+Wide color gamut panel which can cover the DCI-P3 color space
+Variable back-light or back-light dimming technology
+20,000:1 contrast.

required for the HDR standard.  The 27UL550 maxes the brightness and looks very washed out when the fake HDR mode is enabled.  Unless used with very bright lighting (5000 lumens) black looks greyish and IPS glow is much more obvious when HDR enabled, and the panel suffers from a strong and non-reduce-able and non-correct-able blue tint when HDR is enabled since the color controls are locked.  Unfortunately this type of non-performance is normal for most displays which claim to support HDR, especially monitors which sell for under 500$ US.

When displaying SDR (HDTV/REC 709 & sRGB) content the 27UL550 is accurate, looks nearly as good as non-OLED and matte, non-wide gamut LCD can, and only suffers from minor accuracy flaws, the main flaw being the preset blue tint which can be reduced by selecting the SMPTE-C Picture Mode.  The HDR mode is awful as expected, and should not be used.

LG 27UL550 Default vs SMPTE-C Measures
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LG 27UL550 Default vs SMPTE-C RGB Levels
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LG 27UL550 Default vs SMPTE-C RGB Color Temperature
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LG 27UL550 Default vs SMPTE-C Gamma
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LG 27UL550 Default vs SMPTE-C RGB Color Gamut
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The preset color accuracy of the 27UL550 I tested is essentially identical to those of the 27UL650 tested by Belgium Hardware, which along with the 27UL550, are not (even when set to the sRGB and SMPTE-C modes) as accurate as the cheaper Philips 276E8VJSB, though only the 27UL550 has a perceived black depth increasing matte grey bezel.

Dell U2718Q Measurements by Belgium Hardware
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https://nl.hardware.info/product/406980/dell-ultrasharp-u2718q/fotos


LG 27UK650 Measurements by Belgium Hardware
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https://nl.hardware.info/product/428703/lg-27uk650-w/fotos

LG 27UL650 Measurements by Belgium Hardware
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https://nl.hardware.info/product/511129/lg-27ul650-w/fotos

LG 27UL650 sRGB Mode Measurements by Belgium Hardware
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https://nl.hardware.info/product/511129/lg-27ul650-w/fotos

Philips 276E8VJSB Measurements by Belgium Hardware
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https://nl.hardware.info/product/490721/philips-276e8vjsb/fotos

Philips 272P7VPTKEB Measurements by Belgium Hardware
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https://nl.hardware.info/product/372453/philips-272p7vptkeb/fotos
« Last Edit: June 20, 2019, 03:29:20 am by NCX »