When you enable the OpenColorIO plugin, the option to apply OCIO configurations directly within the Viewport appears under the Viewport View Modes. This page describes how to apply your OpenColorIO Configuration Asset to the Viewport.
Prerequisites
You must set up the following in your project to complete the sections below:
An OpenColorIO Configuration Asset. Refer to the OpenColorIO Quick Start for steps on creating this Asset.
Converting the Level Viewport's Colors
Follow these steps to apply color conversion to the Level Viewport.
In the Viewport, click the View Mode button to open its dropdown menu. Choose OCIO Display to open the Display Configuration settings.
In the Display Configuration settings, choose Select an OCIO Asset and select your OCIO Configuration Asset to add it to the Viewport view settings.
The following two settings are the source and destination color profiles. In this example, the source color profile is Utility - Linear - sRGB, and the destination color profile is Output - sRGB Monitor.
Click Enable Display to apply the OCIO color transformation to the Viewport.
When you enable these settings, the Viewport disables Tone Curve and inserts color conversion into the post processing stage of rendering. It does this right after UE applies the Tone Map but before everything else.
The following image shows how the viewport's color is changed by the OpenColorIO configuration.