One of the color correction issues is the pairing of different cameras used in the same production. This tends to be the case with many web, streaming, and scripted projects where budgets and availability generally dictate the mix of cameras to use. I often find RED, ARRI, Panasonic, Sony, DJI and GoPro cameras on the same show. Most NLEs include basic shot matching features, though not flawed. However, few software developers are now tackling this challenge.
One such developer is FilmConvert from New Zealand, the developers of the FilmConvert Nitrate film emulation plugin. Their most recent product is CineMatch, a camera pairing add-on currently available for DaVinci Resolve and Premiere Pro, and coming to Final Cut Pro X in the future. As with Nitrat, CineMatch is a cross-platform add-on that can be purchased for a specific NLE host or as a bundle license to cover all products.
The CineMatch concept is very simple. Most productions have a main or “hero” camera, typically designated as the A-camera. In addition, there are other cameras for cross-sections and alternative angles – B-camera, C-camera, etc. The principle is to match the view of the B and C-cameras with that of the A-camera.
Coping with color science
Each camera manufacturer uses different color science for their products. It will have a completely different look than Sony, Canon or Panasonic. FilmConvert creates its add-ons based on customized camera packages, each for a specific manufacturer and model to match the color science of that camera.
If you have a production that mixes Sony FX9, ARRI Amira and Panasonic GH5, each uses a different camera package. CineMatch is designed to work with Log / RAW / BRAW formats, so there are fewer packages on the CineMatch site than the Nitrate site. This is because many prosumer cameras supported by Nitrate do not record in the log and are therefore not suitable for CineMatch. Since CineMatch uses fewer camera packages, all currently supported camera packages are included in the installer at this point.
Matching basics
To get started, disable all built-in LUTs or remove any you may have added. Next, apply the CineMatch effect to clips in the timeline in Premiere Pro or as nodes in Resolve. In A-camera clips, set the appropriate source camera profile but set the target profile. Set source camera profiles for B-cameras, C-cameras and other clips; however, set the target profile to match the A camera source.
In a case where ALEXA is Panasonic EVA1 as A-glass and B-glass, ALEXA only uses the ALEXA welding profile. EVA1 will be set to EVA1 source, but ALEXA as target profile. Essentially, you are moving all cameras to a color space that matches ARRI ALEXA Log-C color science.
Apply the REC 709 transform to properly view the CineMatch output. However, since CineMatch converts all these clips into a common log space like ARRI’s Log-C, you can leave this transformation inside the clip filter and at a different point, for example as the adjustment layer in a Premiere Pro or as the timeline grading node in Resolve. . As such, CineMatch is not limited to REC 709 / SDR projects.
Additional color correction tools
Ideally, the camera crew should have achieved proper and consistent exposure and white balance between cameras used in a joint setup. Even better if color graphics were also saved initially. In a perfect world, you’re done now. Unfortunately, that’s never the case. You have merged the color space, but that doesn’t automatically match one clip to another. CineMatch includes a comprehensive set of color correction tools to better match and adjust clips. There are white balance and exposure controls for quick adjustments.
If you use the split screen comparison view in Premiere Pro or Resolve, CineMatch HSL curves can be used to improve the match between source and target clips. As with Nitrate, there is a complete set of secondary color controls, including wheels, curves, and levels. Not only can you better match cameras to each other, you can also use CineMatch to meet the most basic grading needs without ever touching Resolve’s grading controls or Premiere’s Lumetri panel.
Working with CineMatch
Although this add-on is marketed for camera pairing, you can use it completely separate from this task. Primarily because of the camera packages. For example, when you shoot with the Panasonic GH5 in a diary profile, no NLE will offer a stock LUT that is correct for this camera. Usually you fix this without a LUT or you apply a generic Panasonic V-Log LUT. This is designed for Varicam’s color science and is not a perfect match for other Panasonic cameras. Close, but not in place. CineMatch allows you to apply a tailored correction for each camera profile, thanks to FilmConvert’s development of a wide variety of professional and professional camera packages.
The second advantage is that you can give the view of other cameras. For example, I’m a fan of ARRI’s color science and really prefer an ALEXA look over many other cameras. I can apply CineMatch to a GH5 clip, set the source profile to GH5 and the target to ALEXA, and give some of that ARRI color to the GH5 clip. While it doesn’t replace shooting with ALEXA and the color conversion might not be absolutely perfect, this is a nice setting that gives a better image than working with the clip alone.
Finally, if you have both CineMatch and FilmConvert Nitrate, it is possible to use the two together. Just pay close attention to the processes and their sequence. In the GH5 / ALEXA example, do the profile conversion in CineMatch. Do not color adjust there and do not apply the REC 709 conversion. Then add FilmConvert Nitrate, set its profile to ARRI settings, and adjust your film emulation and color settings to your taste.
Written for the original ProVideo Coalition.
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