I have HP Elitebook g3 connected to external monitor HP 24" monitor via USB-C and I can't get colours on external monitor even close to what is on Laptop - laptop screen is fine, dragging and dropping Chrome browser window from laptop screen to external display removes all shadows of grey. I tried following all sorts of advice on web, another, another, but to know avail. I can now change resolution and gamma correction per monitor, but I still can't find a way where external monitor displays colours reasonably, currently it looks like no shadows/no greys.
colormgr get-devices-by-kind display
Object Path: /org/freedesktop/ColorManager/devices/xrandr_Chimei_Innolux_Corporation_alex_1000
Owner: alex
Created: June 30 2020, 09:13:18 AM
Modified: June 30 2020, 10:19:34 AM
Type: display
Enabled: Yes
Embedded: Yes
Model: HP EliteBook x360 1030 G3
Vendor: Hewlett Packard
Serial: unknown
Seat: seat0
Scope: temp
Colourspace: rgb
Device ID: xrandr-Chimei Innolux Corporation
Profile 1: icc-4cbae5a38a7c0fa9e4de8532e1bf6acb
/home/alex/.local/share/icc/edid-4a7c449feabad383ba36acbdb55c6200.icc
Metadata: XRANDR_name=eDP-1
Metadata: OutputPriority=secondary
Metadata: OwnerCmdline=/usr/lib/gnome-settings-daemon/gsd-color
Metadata: OutputEdidMd5=4a7c449feabad383ba36acbdb55c6200
Object Path: /org/freedesktop/ColorManager/devices/xrandr_HP_Inc__HP_E243d_CNC90330QF_alex_1000
Owner: alex
Created: June 30 2020, 11:37:49 AM
Modified: June 30 2020, 11:37:49 AM
Type: display
Enabled: Yes
Embedded: No
Model: HP E243d
Vendor: Hewlett Packard
Serial: CNC90330QF
Seat: seat0
Scope: temp
Colourspace: rgb
Device ID: xrandr-HP Inc.-HP E243d-CNC90330QF
Profile 1: icc-5a42c8f4d8898737affa4fa253629350
/home/alex/.local/share/icc/HP.icc
Profile 2: icc-f11d711589cb96e44261fb95baa0c088
/home/alex/.local/share/icc/edid-75ad81bba70229fde551433ac6ce2b21.icc
Profile 3: icc-e6b0b05b63a857001a353db9ac540145
/home/alex/.local/share/icc/edid-1cc561693c489fb94edc90bc7049dfd0.icc
Metadata: XRANDR_name=DP-1
Metadata: OutputPriority=primary
Metadata: OwnerCmdline=/usr/lib/gnome-settings-daemon/gsd-color
Metadata: OutputEdidMd5=1cc561693c489fb94edc90bc7049dfd0