HDR Light Studio uses OpenColorIO color management. For further information on OpenColorIO see http://opencolorio.org/
You may already be using OCIO on your computer and have a path set for your OCIO config file by using an Environment Variable. If you have, HDR Light Studio will honor the OCIO environment variable. You can see this by going to Edit > Preferences in HDR Light Studio.
Panel shows that OCIO Config is set with Environment Variable
If no environment variable is set, HDR Light Studio will default to loading the hdrlightstudio OCIO config installed with HDR Light Studio. A range of OCIO configs are installed in an OCIOConfigs folder, next to the HDR Light Studio application. For example on Windows this location is: C:\Program Files\Lightmap\HDR Light Studio\OCIOConfigs
You can place additional OCIO folders containing config files in that location. The name of the folder will be the name of the listed config. But beware, this folder's contents is replaced when reinstalling HDR Light Studio.
When HDR Light Studio starts it reads all settings in the OCIOConfigs folders. Go to Edit > Preferences and use the dropdown to select the OCIO Config you want to use. You will need to restart HDR Light Studio after this.
On the HDR Light Studio Preferences panel, the OCIO Default View setting will determine which LUT is applied to the interface: Presets Library thumbnails, Canvas and Light Preview images.
There are 3 areas in HDR Light Studio where OCIO Color Management is used:
1. User Interface Display
All lighting content inside HDR Light Studio is handled in linear format - i.e. no color transform = ground truth values. For example, the Render Views, Light Preview and Canvas are all displaying linear image data. So, in order for them to look correct on your display, a display LUT/Color Profile needs applying to this data.
As mentioned above, the OCIO Default View setting in the Preferences panel is applied to Presets Library thumbnails, Canvas and Light Preview images.
The color settings for the Render Views are set via the interface. The color settings for the Render Views are explained here.
2. Loaded Images
When loading an image into HDR Light Studio, a Color Profile is set for the image. By default this is Linear, as we expect to mostly be loading HDR lighting content.
If you do choose a LUT, this Color Profile should tell HDR Light Studio the color profile already baked into the values of the image. HDR Light Studio will then apply a 'reverse' transform to convert the image into linear.
Below shows a low dynamic range image of a flower that has sRGB baked into its values. On the left, the image is washed out, becuase the sRGB image is having a display LUT of sRGB applied to it. So the image looks brighter than expected and the colors washed out. On the right, you can see what happens when the color profile sRGB is selected. The flower image looked correct now it has been converted into linear color space, with a display LUT of sRGB.
3. Production Render (HDR Output files)
When producing production renders of your HDR content. There is an option to set a Color Profile for the output. It is very rare you would want to use this as it would destroy the integrity and lighting look you had created in HDR LIght Studio. We suggest always using a setting of linear or raw. But it does allow a Color Profile to be used perhaps to change the lighting look to a specific feel.
Setting an OCIO Environment Variable
The OCIO environment variable allows you to specify your OCIO config file. Here's an example pointing to some Nuke defaults that ship with HDR Light Studio:
OCIO = C:\Program Files\Lightmap\HDR Light Studio\OCIOConfigs\nuke-default\config.ocio
Please note: When specifiying the OCIO path, slashes should be the correct way for the platform you are on, and not doubled up.
For example: \\cgi-shotgun\library\OCIO_Configs\aces_1.2_marks\config_marks_01.ocio
and not \\\\cgi-shotgun\\library\\OCIO_Configs\\aces_1.2_marks\\config_marks_01.ocio
