Introduction #

The Academy Color Encoding System or ACES is the latest standard in managing color workflows for digital imagery. In simple terms it is a series of transforms between chosen colorspaces to and from the ACEScg colorspace, which is the colorspace we will be doing most of our work in due to its much wider gamut compared to other colorspaces. This explanation is course an oversimplification as color and color management workflows are a complicated subject and going in depth on such a matter goes beyond the scope of this article. Here we will be exploring how to manually setup Blender, Houdini and Natron for working with ACES version 1.0.3 in Linux.

If you would like to learn more about ACES check out the official documentation over at opencolorio.org and the ACES Primer over at acescentral.

If you prefer a more practical guide from an industry professional check out Chris’s CG Cinematography amazing and free ebook.

Lets get started.

Downloading the configuration files #

Download the OCIO configurations from the link below:

https://github.com/imageworks/OpenColorIO-Configs

Extract the contents of the file on a folder somewhere on your system and take note of the location because we will need to reference it on the next step.

We will be using the config.ocio located in the folder for aces version 1.0.3.

Create an Environment Variable for ACES #

Before we go into how to setup each application individually to look for our version of ACES, it is worth noting that most CG applications out there are configured to look for an environment variable on our systems which points to the location of ACES. On this part of the article we will look into how to create such an environment variable in Linux.

To do that we need to edit our .bashrc file. Open a terminal and type the following:

sudo nano ~/.bashrc

Now that we have our bashrc file open in our text editor nano, we will add the following command at the end of the file:

export OCIO="/path/to/my/config.ocio"

After you are done press CTRL+X to save our file and exit. The changes will be applied after we restart the shell. If we want to apply the changes during the current session type the following command:

source ~/.bashrc

To check if our environment variable has been setup as intended we can type the printenv command and pipe it into less.

printenv | less

We should see our OCIO environment variable somewhere inside the list that pops up into less.Press Q to quit less.

Blender #

To setup blender to work with aces in an efficient manner we can create a shell script that exports the config.ocio location as a variable and then starts the application.

Create a file and name it blender-aces.sh. Open it and add the following:

#!/bin/bash

export OCIO="/path/to/my/config.ocio"

/path/to/my/blenderExecutable

We need to make that script executable by typing the following command :

chmod +x /path/to/blender-aces.sh

Our script is now executable. Next we simply need to create a shortcut pointing to that script and place it wherever we like.

Remember to check the Color Management section of Blender’s documentation for its limitations when working with ACES so you don’t run into any sort of trouble.

Natron #

For natron to locate aces we can copy and paste the aces_1.0.3 folder inside the Natron-2.x.x/Resources/OpenColorIO-Configs/ directory.

Open natron and under the Edit menu select Preferences and then Color Management to pick aces_1.0.3. Restart natron and its default colorspace will be set as aces 1.0.3 from now on.

Additionally we have to remember that like similar packages, natron applies a LUT to the viewer which might lead to visually unexpected results when working in ACES. Remember to select the correct LUT in the project settings (hotkey : S) under the LUT tab.

Houdini #

For houdini we need to edit the houdini.env file. The file is located inside in the appropriate houdini version folder located in our users home/ directory. Open houdini.env using any text editor and add the following text to it :

OCIO="/path/to/my/config.ocio"

Clarisse #

To work in ACES within clarisse all you have to do is go under Color Management tab of the Edit menu click Preferences and set the Ocio Config File to look for the path of our config.ocio. Make sure to click Use Ocio Config file to enable clarisse to look for our configuration file.

Done #

On this article we briefly looked into how to download and create an environment variable for aces, how to manually setup Blender, Houdini,Natron and Clarisse to look for it. I hope you found this article useful. If you read the official documentation you might have noticed that this article is similar to the ‘Quick Start for Artists’ entry. If you would like to use a different version of ACES such as v2 or if you’re not an artist then you might want to check out the official documentation for more information on how to do that.

There is a lot more to be said for working in ACES within any of the applications mentioned above and this article does not even barely scratch the surface. You have to convert your textures to acescg, you probably cannot trust your color picker and you have to correctly setup your transforms as you are transferring files from one application to another to make sure you are getting an accurate result. That being said, guides for each application individually are in the works for future entries. If you would like to read a guide for an application not mentioned here feel free to send me a message.