1648876 - Color banding on LCD gradient test PNG

Status: NEW

(Core :: Graphics: Color Management, defect)

Description

[Johannes Pfrang [:johnp]]

Attachment: Clipboard image showing color banding.

The LCD test image on the linked site shows visible banding in Firefox, whereas it renders correctly in Chromium and feh. Firefox is intermittently missing gradients starting with #010101 and ending with #EEEEEE. The image as copied to the clipboard and pasted in the file manager shows the incorrectness and is attached. Firefox shows the image in the URL correctly with gfx.color_management.mode;0.

This was originally reported on reddit and happens with the Basic, OpenGL and Webrender.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:aosmond, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 2

[Andrew Osmond [:aosmond] (he/him)]

I see the banding, but in both Chrome and Firefox. We will need to test more configurations when we resume color management work.

Comment 3

[djfluidz07]

Hi, I have this same issue as OP. Devs, this is how you can reproduce the issue using a generic colour profile offered by Displaycal :

To do this in Windows 10 :

• Install Displaycal, during setup use the default settings allowing Displaycal to handle the colour.
• Close DisplayCal,
• Make sure that DisplayCal profile loader is open in the tasktray and "Load calibration from current display device profile(s) is ticked
• Locate C:\Program Files (x86)\DisplayCAL\tests , right click one of the 40KB icc profiles (not clut) and install profile, the screen should now have a hue (green/magenta tint etc)
• RIght click DisplayCal profile loader in the tasktray, reset video card gamma table, the hue should now disappear, and the screen will return back to normal
• Open Firefox and go to http://www.lagom.nl/lcd-test/ , the hue from the color profile is still being applied even though it is disabled via Displaycal. Chrome and Edge are unaffected.

Yes I know that its a test profile, this is just an example that anybody can reproduce. This is an issue using any profile, even my own profile that I created in displaycal using my own colorimeter (I used default settings).

Firefox is somehow bypassing displaycal and still reading from windows color management at every startup and doing something funky with the grayscale. The only solution I know is to open Windows color management, click the profile, and remove, only then will Firefox look identical to Chrome/Edge.

Please watch this video, where I compare Chrome, Edge and Firefox. I installed one of displaycals test profiles, and even disabled it via Displaycal profile loader (you can see that the desktop looks normal), yet Firefox is still doing something dodgy when the profile is installed.

https://youtu.be/SMYavMrTIoI

Comment 4

[djfluidz07]

Here's an example similar to what OP showed. I installed and used Displaycal to calibrate my monitor. Displaycal is set to handle the colour profile was made using Displaycals default settings (xyzlut+mtx). The profile is installed and enabled via profile associations in Displaycal profile loader.

On my monitor, when the profile is installed and active via Displaycal, Edge/Chrome/Desktop have very minor banding, and overall look smooth from black to white. Firefox is in a world of its own and has a lot more banding.

Adjusting the bitdepth in the profile loader 16 > 8, does not help and only shifts the banding to another location on the grayscale image.

In firefox's about:config, I tried gfx.color_management.enablev4 = true and gfx.color_management.mode = 1, in both Standard and Nightly, to no avail.

Here's a side by side Edge vs Firefox :

https://i.imgur.com/zkClZNV.png

Another thing, when a colour profile is installed, using the black level test at Lagom, black levels are elevated in Firefox compared to chome/edge/desktop. Chrome, edge (new edge) and the desktop show black levels equally.

Comment 5

[djfluidz07]

Oops my bad, I forgot to mention that in the above image, https://i.imgur.com/zkClZNV.png, the profile is installed but disabled via the profile loader (Reset video card gamma table) . As you can see, Firefox is still doing something with the grayscale even when the profile is not active in Displaycal. Edge is unaffected.

Comment 6

[djfluidz07]

If you need me to test anything out please let me know , I'll be more than glad to do so.