System Configuration

Blender Settings

By default, Blender integrates with automatic color management in operating systems and saves images and videos with color space metadata. This means that usually, images viewed in Blender look the same when saved and opened in other applications (on the same computer). Particularly image viewers, video players and browsers that also use automatic color management.

Traditionally, VFX software has relied on more manual configuration, though with wide gamut and HDR automatic color management is becoming more common. To use more traditional manual configuration Blender, turn off display emulation.

Display Emulation

Automatic(自動):

Display images consistent with most other applications, to preview images and video for export.

The choice of display in Blender specifies the target display color space for rendered images and video files, or game assets to export. Colors will be clipped to the gamut and HDR range of the chosen target display.

For example, if you have a P3 HDR monitor, you can preview what the image will look like when saved as sRGB, Display P3 or HDR by switching the display.

Off(オフ):

Directly output image as produced by OpenColorIO. For accurate results, this requires the choice of display in Blender to match the system configuration and actual display device. A mismatch will give inaccurate results.

Emulation is not supported with older OpenColorIO configurations.

Enabling Wide Gamut and HDR

For viewing wide gamut and HDR colors, a monitor with those capabilities is required.

  • macOS: Available on any Apple Silicon device.

  • Linux: Use Wayland, and set the Vulkan backend in the Blender system preferences.

  • Windows:

    • For wide gamut, enable "Automatically manage color for apps" in the Windows display settings.

    • For HDR, enable "Use HDR" in the Windows display settings.

    • Set the Vulkan backend in the Blender system preferences.

Wide Gamut

On Windows and Linux, monitors are not always calibrated for accuracy by default. sRGB colors may be mapped to the P3 gamut of the monitor, which makes all colors more vibrant.

Enabling "Automatically manage color for apps" on Windows or using a good display profile can correct for this.

HDR & Tone Mapping

HLG and PQ standards support up to 1000 nits and 10000 nits respectively, but physical monitors only have a limited range. When HDR colors in the video exceed the limits of the display, video players apply tone mapping to bring the video into the available range. Blender does not currently perform automatic HDR tone mapping, and simply clips the colors.

HLG and PQ standards are defined in absolute nits. This makes sense in a controlled cinema environment. On a computer monitor or TV, brightness can be adjusted, and this affects all SDR and HDR content viewed on the device.

In this context, the more important metric is the headroom above reference white. This is how much brighter a color can be compared to an SDR white color. In Blender, 100 nits is reference white. That means that an HDR view transform with 1000 nits requires 10x headroom to be displayed fully, before tone mapping or clipping kicks in.

The available headroom changes with the display brightness. Increasing the brightness decreases the amount of headroom. Lowering the brightness increases the headroom.

For accurate viewing conditions, HDR monitors can be calibrated to absolute nits. On macOS, the "HDR Video" display preset locks display brightness to match the PQ standard.

Gamma Discrepancies

Transfer functions exist to efficiently store and display 8 bit colors. Common transfer functions are sRGB, Gamma 2.2 and Gamma 2.4.

Ideally, encoding and decoding of images would always use matching transfer functions. And this is how it works in many cases.

However, on computers there is a peculiar convention where images are encoded as sRGB, while usually monitors decode with gamma 2.2. This depends on the specific hardware, operating system and configuration, and it is not true in general. But many images, games and websites have been created to be viewed under these conditions.

As long as SDR content is both created and viewed on such computers, there is no problem. However, when creating content for TV or cinema, or when creating HDR content, what you see on your computer may not match your target.

Differences may be subtle unless you know what to look for. But if you need accurate calibration, here are some hints to help you set things up.

Manual Color Management

Traditionally, for accurately viewing content for TV or cinema on a computer there are a few solutions.

  • Keep the monitor at Gamma 2.2, and use a Gamma 2.2 display in OpenColorIO.

  • Calibrate the monitor for sRGB, and keep using the default sRGB display in OpenColorIO.

  • Change both the monitor calibration and OpenColorIO display to Gamma 2.4.

All involve carefully matching the OpenColorIO display to the monitor transfer function, so they cancel out exactly. In Blender, this involves turning off Display Emulation so the transfer function is used as-is.

Automatic Color Management

Modern color management on operating systems does not simply pass on colors directly from the application to the monitor. Rather both the application and the monitor are matched to an absolute reference, and the operating system performs the appropriate conversions.

Blender display emulation is designed to work with automatic color management. To control the accuracy, it is then the operating system and monitor that must be configured once with the appropriate transfer function.

HDR

HDR display requires automatic color management to be used. Enabling HDR in the operating system settings often affects gamma for all applications.

  • On Windows, enabling "Use HDR" makes the transfer functions cancel out. This means HDR content is displayed accurately, and may also be helpful for viewing SDR content for TV or cinema. But it changes the appearance of all applications and images compared to many SDR monitors.

  • On macOS, the default "XDR" display preset can display both SDR and HDR content. However, for accurately viewing HDR content there is a "HDR Video" display preset. Like HDR mode on Windows, this cancels out the transfer functions and changes the appearance of all applications and images.

  • On Linux, Wayland color management supports displaying both SDR and HDR content similar to macOS. Because Wayland does not have a distinct HDR mode, Blender automatically switches between sRGB and gamma 2.2 image encoding depending on whether an SDR or HDR display was chosen. This way both can be accurate with the same system configuration.