# Colour management: ICC profiles and why wide-gamut looks wrong

> How Windows applies colour profiles per display, why saturated panels oversaturate the desktop, and where HDR changes the rules.

**Tested on**

- Build: 26300.9457
- Edition: Pro (26H2)
- Architecture: x64
- Evidence: E1
- Verified: 2026-10-29

## The short answer

A wide-gamut monitor shows **more saturated colours** than sRGB content was authored for. Without colour management, everything on the desktop looks oversaturated: reds glow, skin tones go orange, icons look neon.

Two things fix it, and they are not the same:

1. **An ICC profile associated with the display** — tells Windows what the panel actually does.
2. **Applications that honour the profile** — most do not, by default.

The desktop shell, most browsers' UI, and many apps are **not** colour-managed. That is why a calibrated monitor can still show a wrong-looking Windows.

## How Windows applies profiles

- Windows keeps a profile **per display** (`C:\Windows\System32\spool\drivers\color`).
- The association is per-user and per-device (`Color Management` control panel → Devices).
- **Colour-managed applications** (Photoshop, Lightroom, some browsers with flags) read the profile and convert.
- **Non-managed applications** send sRGB values straight to the display, which renders them at full panel saturation.

```powershell
# what profiles exist and which is default
Get-ChildItem "$env:SystemRoot\System32\spool\drivers\color" -Filter *.icm | Select-Object Name
Get-CimInstance -Namespace root\wmi -ClassName WmiMonitorID |
  Select-Object InstanceName,ManufacturerName,UserFriendlyName
```

Windows has no supported cmdlet for "associate profile X with display Y" — that is the Color Management control panel or the vendor tool.

## The three settings people confuse

| Setting | Where | What it does |
|---|---|---|
| **ICC profile association** | Color Management | tells the OS about the panel |
| **Windows HD Color / HDR** | Settings → Display | switches to an HDR signal |
| **Monitor OSD preset** | the panel itself | sRGB / Adobe / custom gamut clamp |

A monitor with an **sRGB clamp** in its OSD solves the desktop-oversaturation problem without any software. That is often the honest fix: clamp, then calibrate.

> **Caution: Do not 「fix」 oversaturation with the graphics driver saturation slider**
>
> Lowering digital vibrance/saturation in the GPU control panel shifts everything, breaks gradients, and is invisible to colour-managed apps. Use an sRGB clamp or a proper ICC profile.

## When you actually need calibration

- **Photo/video work** where the output must match a known standard.
- **Multi-monitor setups** where two panels must look similar.
- **Print matching** — then you need the printer profile too.

A hardware calibrator produces a per-panel ICC profile from measurements. Without one, you are guessing, and vendor "calibration reports" are per-unit lottery tickets.

## HDR changes the rules

With HDR enabled:

- the signal is **PQ/HLG**, not sRGB;
- SDR content is tone-mapped by Windows (the SDR brightness slider);
- ICC profiles for SDR no longer describe what the panel does;
- per-app HDR handling decides whether content is converted or passed through.

That is why HDR looks wrong on a machine with a correct SDR profile — different pipeline, different mapping. See [the HDR chain](https://winbook.fyi/en/hardware/display/hdr-chain/).

## A practical order

1. Set the monitor OSD to **sRGB** if the desktop looks oversaturated.
2. Install the vendor **monitor driver** (it carries the EDID and often a profile).
3. Associate the profile in Color Management.
4. Only then calibrate, if the work requires it.
5. Leave HDR off for desktop work unless the panel handles it well.

## Related

- [Windows HDR: the whole chain](https://winbook.fyi/en/hardware/display/hdr-chain/)
- [Monitor choice and VRR](https://winbook.fyi/en/hardware/display/monitor-choice/)
- [Fonts and CJK rendering](https://winbook.fyi/en/windows/media/fonts-cjk/)

## Lab boundary

E1. Colour pipeline behaviour is documented by Microsoft and defined by the ICC/ISO standards. The lab has no physical display, so no profile was measured.

## Sources

- [Microsoft Learn — Display drivers](https://learn.microsoft.com/en-us/windows-hardware/drivers/display/)
- [Microsoft Learn — DISPLAYCONFIG_VIDEO_SIGNAL_INFO](https://learn.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-displayconfig_video_signal_info)
- [Microsoft Learn — High DPI and display](https://learn.microsoft.com/en-us/windows/win32/hidpi/high-dpi-desktop-application-development-on-windows)

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Source: https://winbook.fyi/en/windows/media/colour-management/