I was recently alerted to the new Amira Color Tool by Michael Phillips’ 24p blog. This is a lightweight ARRI software application designed to create custom in-camera looks for the Amira camera. You do this by creating custom color look-up tables (LUT). The Amira Color Tool is available as a free download from the ARRI website (free registration required). Although the application is designed for the camera, you can also export looks in a variety of LUT file formats, which in turn, may be installed and applied to footage in a number of different editing and color correction applications. I tested this in both Apple Final Cut Pro X and Avid Media Composer | Software (v8) with good results.
The Amira Color Tool is designed to correct log-C encoded footage into a straight Rec709 offset or with a custom look. ARRI offers some very good instructions, white papers, sample looks and tutorials that cover the operation of this software. The signal flow is from the log-C image, to the Rec709 correction, and then to the CDL-based color correction. To my eye, the math appears to be floating point, because a Rec709 conversion that throws a shot into clipping, can be pulled back out of clipping in the look tab, using the CDL color correction tools. Therefore it is possible to use this tool for shots other than ARRI Amira or Alexa log-C footage, as long as it is sufficiently flat.
The CDL correction tools are based on slope, offset and power. In that model slope is equivalent to gain, offset to lift and power to gamma. In addition to color wheels, there’s a second video look parameters tab for hue intensities for the six main vectors (red, yellow, green, cyan, blue and magenta). The Amira Color Tool is Mac-only and opens both QuickTime and DPX files from the clips I tested. It worked successfully with clips shot on an Alexa (log-C), Blackmagic Cinema Camera (BMD Film profile), Sony F-3 (S-log) and Canon 1DC (4K Canon-log). Remember that the software is designed to correct flat, log-C images, so you probably don’t want to use this with images that were already encoded with vibrant Rec709 colors.
To use the Amira Color Tool, import your clip from the application’s file browser, set the look and export a 3D LUT in the appropriate format. I used the DaVinci Resolve setting, which creates a 3D LUT in a .cube format file. To get this into FCP X, you need to buy and install a LUT filter, like Color Grading Central’s LUT Utility. To install a new LUT there, open the LUT Utility pane in System Preferences, click the “+” symbol and navigate to where the file was saved. In FCP X, apply the LUT Utility to the clip as a filter. From the filter’s pulldown selection in the inspector, choose the new LUT that you’ve created and installed. One caveat is to be careful with ARRI files. Any files recorded with newer ARRI firmware are flagged for log-C and FCP X automatically corrects these to Rec709. Since you don’t want to double up on LUTs, make sure “log processing” is unchecked for those clips in the info tab of the inspector pane.
To use the custom LUTs in Media Composer, select “source settings” for the clip. Go to the color management tab and install the LUT. Now it will be available in the pull-down menu for color conversions. This color management change can be applied to a single clip or to a batch of clips within a bin.
In both cases, the source clips in FCP X and/or Media Composer will play in real-time with the custom look already applied.
©2014 Oliver Peters