I shoot with the Sony a7S II, and I’m really happy with the images it produces. Unfortunately, it’s also limited by a codec which restricts it to 8-bit, low data rate video capture. In the real world, this manifests as digital artifacts that reduce the resolution of your footage and make it harder to color grade. I use the process below to clean up my footage before editing, but I’d recommend this workflow for any 8-bit video or footage with visible noise.
Digital noise is one of the biggest obstacles to high-quality video. Whereas analog noise can be aesthetically pleasing, digital noise looks cheap and pixelated. It’s a combination of the noise of your camera sensor (created by amplifying light, more prevalent at higher ISO values) and the artifacts created by the codec (created by compression, more prevalent at low data rates). A high-quality denoiser can make a world of difference on your footage; I’m using Neat Video, and I’ve been really impressed by its capabilities. Here’s a dramatic example (click here for full-size):
This kind of noise reduction is most visible on smooth gradients, as this is where low data rate codecs attempt to compress the most information. However, it’s also visible on more detailed shots (click here for full-size):
You can clearly see the pixelation and abrupt transition between colors on the artist’s cheek; when noise reduced, the skin is much smoother. The bokeh in the background is also much improved. At the same time, the denoiser does a great job of preserving detail where it’s present (in the face, hair, and clothes).
Color Correct & Grade
Each of these is a process unto itself, but that’s not the focus of this article. Color correct and grade your footage as necessary. If you’re applying visual effects (such as a vignette), this is the stage to do that.
Note: If you’re editing in the same software you’re using for color grading, you could also put together your cut at this stage. I prefer to render out the graded files and edit those, as it allows for much smoother playback (see below).
When I’m applying grain, I’m not necessarily attempting to create a vintage look (although you could); I’m mainly using it to dither. Dithering is a universal concept in the digital world (it applies to audio as well as video), where low-level/non-uniform artifacts are masked by the application of uniform noise. Grades, masks and vignettes can introduce banding & artifacts to your footage, and grain is a powerful tool to smooth it back out. It’s more aesthetically pleasing than noise, and works perfectly as a final stage to add texture to your footage.
As I’m not looking to directly emulate film, I use rGrain’s digital stock, which is clean and free from scanned artifacts. I drop it in as a clip above my footage, using overlay mode to blend it in at anywhere from 25% to 100% opacity (depending on the look you’re going for). Whatever method you use, make sure that grain is last step in the chain. Here’s an example of footage with grain added (click here for full-size):
As you can see, the grain smooths gradients and adds a beautiful texture to the background without obscuring the details of the hair or face.
Render to 10-Bit 4:2:2
Once the footage is color graded and grain has been applied, I’m rendering out to 10-bit 4:2:2, which preserves any new color information created through the denoising & dithering process. DNxHR HQX is a great intermediate format for this. Rendering out the files before editing takes a huge processing workload off my editing software, as all it’s handling now is cuts, crossfades and titles. This makes for much faster renders, which is very useful when making small revisions for clients.
This process adds time to your workflow, but it makes a noticeable difference in the quality of your footage. It allows you to push your color grades much farther before running into digital artifacts, and in low-light situations with visible noise, it’s absolutely necessary.
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