Extreme Black Level Clipping on XPS 15 9550?

Discussion in 'Dell XPS and Studio XPS' started by Silentpower, Dec 6, 2015.

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  1. Silentpower

    Silentpower Notebook Enthusiast

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    Can anyone else with an XPS15 with the 4k display tell me how their black levels are? I have been noticing really bad banding in shadows in videos, and I initially thought it was just poor video compression. However, now it is catching my eye constantly even in pictures, videogames, website backgrounds, etc.

    I have tried tweaking the premier color settings, but nothing works aside from dropping the black level way down to the point where all shadow detail is lost. It seems like dark colors are being merged together in even moderately dim scenes, resulting in extreme blockiness in the shadows.

    I have tried calibration test images like this one: http://prohardver.hu/dl/cnt/2003-05/201/dispmate/black_level_adj_test.png and was unable to get blocks 1 through 4 to differentiate from the background, even when turning black level, contrast, or brightness to max. Other test images have similar results, and it seems like the first few blocks that are visible have the same shade/brightness. This reminds me of issues that I've had before when I've had graphics cards outputting PC blacklevels to a regular TV, resulting in black/white crush. But I can't seem to find a way to adjust this for the laptop display, and shouldn't this be configured properly by default?

    I have output the same image to my 1080p TV (which is a fairly good, but not great display, and nothing close to a professional monitor) via hdmi and have had no issues getting all blocks to display properly by messing with the contrast, brightness, and black level settings.

    Am I missing something here? Is there a possible display driver conflict or something else? I had heard of Dell's adaptive brightness, but I didn't think it would have anything to do with clipping of blacks. The fact that even max display levels have no impact, and it is not reproducible on an external display leads me to believe that there is some sort of clipping/compression at the firmware level.
     
  2. Annihil

    Annihil Notebook Consultant

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    You are right, even at max brightness I cannot distinguish any square of the first row (1-8), a little bit 7 and 8 to be honest but is really hard. (XPS 15 4K)
    Tried on another computer and it was easily noticeable.
    Damn, another issue :(
     
  3. Silentpower

    Silentpower Notebook Enthusiast

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    I put a post on the dell support site. http://en.community.dell.com/support-forums/laptop/f/3519/t/19663748?rfsh=1449455605759

    I am certain this is a video level issue, as I have replicated the effect with extreme whites as well. I just don't understand how something so obvious could slip through. Outputting proper video levels is the first and most basic part of display calibration, well before fine tuning contrast, brightness, color gamut, etc.

    I noticed that the intel display control panel has advanced options that allow you to change video levels for external displays, but when I select the laptop display it says that the display doesn't support advanced settings. UGHHHH.
     
  4. Alant30

    Alant30 Notebook Enthusiast

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    i have tried other calibration images on the web and my xps15 looks ok. Do you know if we are to resolve all the black squares in the image you posted? For the image you posted, I cant resolve 1-6 but i suspect that is normal
     
  5. Silentpower

    Silentpower Notebook Enthusiast

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    As I said, my tv is able to resolve all blocks without issue. Maybe that test image isn't right (per the instructions you should be able to distinguish all blocks). But I've tried others as well such as http://gonedigital.net/wp-content/uploads/AVStest-black.png

    My TV is nearly able to distinguish down to the reference black level (stops at 17). However, my laptop is only able to resolve down to around 22.
     
  6. W123

    W123 Notebook Consultant

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    Try a calibrator? Might just be that gamma is off from the factory. That will definitely kill shadow detail
     
  7. Silentpower

    Silentpower Notebook Enthusiast

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    I don't have a colorimeter, so I can't do a full calibration. I did mess with gamma in premier color and nothing changed (low level blacks were all clipped regardless of how bright the rest of the boxes were). However, after uninstalling premier color and restarting, I was able to use gamma and contrast adjustments in the intel control panel to mitigate most of the black clipping without destroying the whites. It still seems a bit off though. I have some BB gift cards, so maybe I will buy a colorimeter and try to see how good of a calibration I can get. I don't understand why premier color is forcing blacks to be clipped though. Maybe there is a conflict between the software and the intel driver? That would seem like a huge oversight, and negates any benefit of having the premier color software.
     
  8. Annihil

    Annihil Notebook Consultant

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    I'm able to distinguish every box with gamme set to 1.3 in intel graphics setting (haven't installed dell premier color) but then the whole screen is a little bit to bright...
    [​IMG]
     
  9. Alant30

    Alant30 Notebook Enthusiast

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    The contrast looks too low when you adjust the gamma to remove the black clipping. I also uninstalled dell premier color. Is there anywhere I can get back dell premier color application for xps15? It seems I have lost the factory calibration profile?
     
  10. MLev1777

    MLev1777 Notebook Consultant

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    Dell released a new version of Premier Color that is actually stable and I tested several presets. I was also able to configure the gamma and black level to view all of the boxes in the above example, however everything else looked terrible. Currently on Cinema preset, and I think everything looks pretty much perfect.
     
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