Question about measured contrast ratio

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This topic contains 8 replies, has 2 voices, and was last updated by  dvdx SourceForge (@dvdx-sourceforge) 4 years, 2 months ago.

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  • #1044

    Hello. I just got a spyder4elite from a friend and attempted to calibrate using dispcal. My monitor is the Samsung S34E790C with a VA panel and a supposed contrast ratio of 3000:1. I reset the monitor to factory defaults and proceeded with a fast calibration with a 6500K white point and 2.2 gamma. The result seems satisfactory but the contrast ratio was 825.5:1 which surprised me since I was expecting a figure near the claimed 3000. Here’s my measurements report (sorry for the long image): http://i.imgur.com/ca8Dlnx.png

    Is this correct or am I missing something; could you please shed some light on this? Thanks for your time.

    #1045

    Florian Höch (@fhoech)
    Administrator
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    Hi, it seems you have set a black level target and possibly also enabled black point hue correction. As you can’t force a balck point that’s lower than what your display is capable of, and you can only add, not subtract from black to correct the hue, your black point will be raised. So in short to get the native contrast ratio:

    • Do not set a black level target
    • Do not enable black point correction (“Auto” unchecked, correction level 0%)

    You’ll have to re-do the calibration and profile with these settings.

    • This reply was modified on 2015-09-14 00:18:01 by fhoech.
    #1046

    Unfortunately, even with the adjusted settings the contrast ratio hasn’t improved. I lowered the brightness to 125 cd/m² this time round and black luminance was measures as 0.1728 cd/m².

    I want to show you this review of the monitor: https://pcmonitors.info/reviews/samsung-s34e790c/

    If you scroll down to “Contrast and brightness” they have a table with the black luminance values they were able to achieve which interests me. My monitor easily reaches brightness levels 330+ but has yet to go as low as 0.05. I’m starting to think that maybe the spyder4 is not sensitive enough to pick up values that low.

    #1047

    Florian Höch (@fhoech)
    Administrator
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    Please attach the profile. There’s a button next to “Settings” that allows you to create a compressed archive.

    #1048

    Right. Here you are.

    #1049

    Florian Höch (@fhoech)
    Administrator
    • Offline

    Ok, the profile and measurement file reflect the actual measured black level. The profile and calibration do not raise the black level, so it looks like a limitation of the Spyder4.

    #1050

    I appreciate you looking into this, big thanks. But do I need to calibrate with a better device to achieve the contrast my monitor is capable of? Which one would you recommend?

    #1051

    Florian Höch (@fhoech)
    Administrator
    • Offline

    You already have achieved the full contrast ratio, your Spyder4 is just not able to measure it correctly. There’s no immediate need to get another instrument, although either the ColorMunki Display or i1 Display Pro would be a step up (both devices have identical hardware, but the ColorMunki display’s measurement speed is limited in its firmware).

    ColorMunki Display on Amazon   i1Display Pro on Amazon  
    Disclosure: As an Amazon Associate I earn from qualifying purchases.

    #1052

    Thank you again for being such a great help! I’ve sent a meagre donation your way for now, I’ll be sure to send more once I’ve topped up my paypal account.

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