[Touch-packages] [Bug 1785764] Re: Some applications render too dark when a 4K screen is attached.

2018-08-16 Thread Daniel van Vugt
Great!

I checked and it was only a year ago that the rest of us noticed the
problem and found a solution (including Matthew Paul Thomas, Robert
Ancell and myself).

If the problem is still occurring in 18.04 then we need to do something
about it. That something is to ensure Ubuntu ships with NO ACTIVE colour
profile, which has been the fix for all of us so far...


** Tags added: bionic

** Summary changed:

- Some applications render too dark when a 4K screen is attached.
+ Ubuntu default colour profile distorts colours on some machines (white looks 
green, too dark, or under-saturated)

** Package changed: ubuntu => colord (Ubuntu)

** Changed in: colord (Ubuntu)
   Status: Invalid => Confirmed

** Also affects: gnome-control-center (Ubuntu)
   Importance: Undecided
   Status: New

** Changed in: gnome-control-center (Ubuntu)
   Status: New => Confirmed

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https://bugs.launchpad.net/bugs/1785764

Title:
  Ubuntu default colour profile distorts colours on some machines (white
  looks green, too dark, or under-saturated)

Status in colord package in Ubuntu:
  Confirmed
Status in gnome-control-center package in Ubuntu:
  Confirmed

Bug description:
  Using Ubuntu 18.04.1 LTS 
  Running on an i7-6700k with a GTX 1080
  Reproducible with nvidia-driver-396 or xserver-xorg-video-nouveau
  and a single 4K screen (TV) connected via HDMI.

  The issue:
  Any dark content displayed by an effected application (e.g. a very dark image 
or dark themed web page) is much darker than intended making it almost 
unusable. 

  This only effects applications that are launched when the 4K screen is
  connected. If i disconnect the 4K screen, launch the app via a
  different 1080p monitor then reconnect the 4K screen the app remains
  unaffected.

  The only apps i have found so far that are effected by this are Google
  Chrome and Image Viewer. That said this is only noticeable when the
  app is displaying dark contend so if other apps are affected it may be
  impossible to tell.

  The attached screenshot uses a black to white gradient image to clearly 
demonstrate the issue. 
  Is seems like it may be an issue with colour depth as bellow a certain 
brightness it just goes strait to black.

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[Touch-packages] [Bug 1785764] Re: Some applications render too dark when a 4K screen is attached.

2018-08-09 Thread Daniel van Vugt
Always remember a TV is not a monitor. Monitors are made to respond to
colour more accurately than TVs, out of the box. If you want to use a TV
as a monitor then you will very likely need to change a lot of settings
in the TV itself to make it behave more like an accurate monitor. I know
it's annoying, hardly any TV manufacturers do this out of the box.

The first thing to remember is that the HDMI spec requires that HDMI
displays respond to colour differently than non-HDMI (computer monitor)
displays. The HDMI spec says that all values 0-16 are full black and all
values 235-255 are full white. This is called limited RGB mode and you
will need to tell BOTH the Nvidia driver and the TV to switch to full
range RGB mode instead so that they render shades more accurately like a
monitor.

As a second preference, you should be able to tweak the gamma values in
the nvidia settings utility. Your gamma exponent looks too high so
reducing it will bring back those missing shades.

You can also choose a colour profile in Settings > Devices > Color which
may help to change the gamma curves to your liking.

I hope you find a solution in one of those.

Unfortunately since you're using a graphics driver that's not from the
Ubuntu archive, we can't really handle bug reports about that here.

If you are willing to downgrade the driver to a supported version like
https://launchpad.net/ubuntu/+source/nvidia-graphics-drivers-390 then
you can open a new bug report by running:

  ubuntu-bug nvidia-driver-390

** Package changed: xorg (Ubuntu) => ubuntu

** Changed in: ubuntu
   Status: New => Invalid

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You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1785764

Title:
  Some applications render too dark when a 4K screen is attached.

Status in Ubuntu:
  Invalid

Bug description:
  Using Ubuntu 18.04.1 LTS 
  Running on an i7-6700k with a GTX 1080
  Reproducible with nvidia-driver-396 or xserver-xorg-video-nouveau
  and a single 4K screen (TV) connected via HDMI.

  The issue:
  Any dark content displayed by an effected application (e.g. a very dark image 
or dark themed web page) is much darker than intended making it almost 
unusable. 

  This only effects applications that are launched when the 4K screen is
  connected. If i disconnect the 4K screen, launch the app via a
  different 1080p monitor then reconnect the 4K screen the app remains
  unaffected.

  The only apps i have found so far that are effected by this are Google
  Chrome and Image Viewer. That said this is only noticeable when the
  app is displaying dark contend so if other apps are affected it may be
  impossible to tell.

  The attached screenshot uses a black to white gradient image to clearly 
demonstrate the issue. 
  Is seems like it may be an issue with colour depth as bellow a certain 
brightness it just goes strait to black.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+bug/1785764/+subscriptions

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[Touch-packages] [Bug 1785764] Re: Some applications render too dark when a 4K screen is attached.

2018-08-09 Thread Brian Murray
** Package changed: ubuntu => xorg (Ubuntu)

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You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1785764

Title:
  Some applications render too dark when a 4K screen is attached.

Status in xorg package in Ubuntu:
  New

Bug description:
  Using Ubuntu 18.04.1 LTS 
  Running on an i7-6700k with a GTX 1080
  Reproducible with nvidia-driver-396 or xserver-xorg-video-nouveau
  and a single 4K screen (TV) connected via HDMI.

  The issue:
  Any dark content displayed by an effected application (e.g. a very dark image 
or dark themed web page) is much darker than intended making it almost 
unusable. 

  This only effects applications that are launched when the 4K screen is
  connected. If i disconnect the 4K screen, launch the app via a
  different 1080p monitor then reconnect the 4K screen the app remains
  unaffected.

  The only apps i have found so far that are effected by this are Google
  Chrome and Image Viewer. That said this is only noticeable when the
  app is displaying dark contend so if other apps are affected it may be
  impossible to tell.

  The attached screenshot uses a black to white gradient image to clearly 
demonstrate the issue. 
  Is seems like it may be an issue with colour depth as bellow a certain 
brightness it just goes strait to black.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1785764/+subscriptions

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