ICC Color Profiles

Dux Shell

ICC Color Profiles

The dms icc command applies ICC color profiles per output and manages per-output color temperature, on top of the global night light schedule. Both use wlr-gamma-control-unstable-v1, the same protocol the night light relies on.

Quick Start

# Show profiles in the profile directory and their current assignments
dms icc list

# Inspect a profile before applying it
dms icc info ~/profiles/display.icm

# Apply it to one output
dms icc apply DP-1 ~/profiles/display.icm

# Show what is active right now
dms icc status

# Set a per-output color temperature, and go back to the schedule later
dms icc set-temp DP-1 7000
dms icc set-temp DP-1 0

# Remove the assignment again
dms icc remove DP-1

Commands

Command	Description
dms icc list	List profiles found in the profile directory together with the current assignments
dms icc status	Show per output the profile, version, color space, whether the ramp is active and the temperature override
dms icc info <file>	Show details of an ICC/ICM file (description, version, color space, vcgt)
dms icc apply <output> <file>	Apply a profile to a specific output
dms icc remove <output>	Remove the profile from a specific output
dms icc set-temp <output> <kelvin>	Set a per-output color temperature (1000-10000K), independently of the night light schedule; 0 removes the override

Profiles are looked up in the DMS config directory for the running compositor, <config dir>/<compositor>/dms/icc — for example ~/.config/niri/dms/icc on niri, ~/.config/hypr/dms/icc on Hyprland and ~/.config/mango/dms/icc on MangoWC. Output names are connector names as reported by the compositor, such as DP-1, DP-2, HDMI-A-1 or eDP-1.

Settings UI

Display Config → each output card carries both controls:

• Color Profile — browse to a .icc/.icm file and apply it. The row shows the profile description together with version, color space and whether the ramp is currently active; the remove button clears the assignment. The info button next to it opens the profile details: version, class, color space, tone curve, video card gamma table, white point with its color temperature, file size, modification time and path.
• Color Temp — an independent 3000K–10000K temperature per output, applied independently of the night light schedule, so each display can keep its own white point and its own on/off state (the value is per output, and the range is wider than the night light's). For an output with a profile the temperature is composed on top of the profile ramp, which is treated as measured at 6500K; setting it back to Default turns the override off.

Both settings apply immediately and survive restarts.

Per-output values win over the night light schedule: a display with its own temperature keeps it whether the schedule is enabled or not, while displays without one follow the schedule and fall back to 6500K when it is disabled.

Configuration

Assignments live in the night light configuration of the running compositor, ~/.config/niri/dms/wayland.json on niri (Hyprland and MangoWC use their own directory):

{
  "iccProfiles": {
    "DP-1": "/home/user/profiles/display.icm",
    "eDP-1": "/home/user/profiles/laptop.icm"
  },
  "outputTemps": {
    "DP-1": 7000,
    "eDP-1": 6500
  }
}

iccProfiles maps an output name to the profile path, outputTemps maps an output name to its color temperature in Kelvin.

Notes

• ICC ramps are applied even while the night light schedule is disabled: outputs with a profile get their measured ramp, outputs without one stay at a neutral ramp so nothing is tinted unexpectedly.
• Profiles are re-applied after resume and when an output is hot-plugged.
• The compositor must expose wlr-gamma-control-unstable-v1. If dms icc status shows no outputs, the running compositor does not provide it.
• Only a profile that carries a vcgt table can be applied: that tag holds the video card gamma table the GPU ramp takes. The rTRC/gTRC/bTRC tags describe the display's own transfer function (roughly t^2.2 for a normal monitor), so dms icc info reports them but they are never written into the ramp — applying a profile without vcgt is refused instead of washing the display out.
• Night light contrast, gamma and schedule settings in the same file keep working as before; ICC and per-output temperature are applied in addition to them.
• DMS only ever writes iccProfiles and outputTemps to that file: the night light fields are owned by the shell, so applying a profile never persists the night light state the daemon happened to hold.