Saturday, September 19, 2015

How I color correct my Vlog shots

With this blogpost I am sure I am not adding any original views to the community of videographers out there, especially the pro's among them, but I'm simply sharing my own experience with GH4 shooting Vlog footage.

I am using FCP as my NLE of preference. In every new set of shots, that I usually shoot in one session, I am trying to fix a representative shot first, and then create a preset based on those fixes that I subsequently apply to the remaining shots. This approach usually provides me with satisfactory results; nevertheless, I tend to go over all the remaining shots once more, observe their look-'n-feel that the preset generated, and review their waveforms, and, if necessary, I do some further fine-tuning. I believe this is exactly what most of you out there are doing as well

As the first shot is concerned, I work in non-aggressive iterative steps. The pictures attached hereunder show the sequence of my approach. Since the release of the Vlog-L profile on the GH4, I shoot in that style with +2 stops overexposure. As you can witness in the first screen-capture hereunder, this GH4 profile generates a highly washed out image that has the advantage that its luma waveform is spread between 25% and 75%. 

I first push the shadows to make the luma wave touch the zero line. Subsequently, to my personal taste, I push midtones down as well. Next, I push highlights to touch the 100% line at the top of the luma diagram. Doing this pulls the shadows and midtones higher as well. Therefore, during a second iteration cycle, I am repeating the process by fine-tuning the three exposure components to ensure the final waveform covers the best part of the entire spectrum from 0 to 100% and the resulting image shows the proper tonality and contrast, and above all it is pleasing to the eye. Of course, I don't just do that mechanically only based on waveform shapes, otherwise even computers could learn to do that automatically. At each stage I observe the output frame to get convinced that the result is aesthetically pleasing. 

Eventually, if the white balance of the clip happened to not be to my liking I do correct that in the Color tab of the Color Board, and that after fixing luminosity and contrast in the Exposure tab. In the example below, as can be seen in the RGB parade waveform, the color balance looks acceptable, and didn't need adaptation. Only the Saturation I pushed globally a little bit for reasons of personal taste. 

A sphere look-'n-feel (colorisation) I finally apply using one of many available 'looks' plugin and if necessary some fine-tuning of its parameters, again to my personal taste. In the example shown here, I used mLut by MotionVFX and applied their "metal suit" preset. I could have used anything else for that matter. The result is shown in the last picture in this series.

This has been a simple cycle, quick and dirty, suitable to us, gifted amateurs, who can't afford doing expert colorisation and log corrections with Pro gear like Da Vinci Resolve, regardless whether it's been made available for free by its owners BlackMagic.


Shot in its original state. On the left the Luma and RGB Parade waveforms, on the right the color board for tuning and fine tuning. 
First step pushing down the shadows to touch the zero line.

Doing the same with the midtones to my liking.

Pushing up the highlights, that pulls shadows and midtones higher as well.

Push shadows down again to touch zero.

Same for midtones to my liking.

As highlights moved down too, push them back up again.

As exposure got fixed, do color corrections next. In my case only the global saturation was pushed. The RGB parade shows all three RGB waveforms in balance; no corrections added.

Eventually, a purchased plugin look applied. In this case it was the metal suit look of MotionVFX's mLUT plugin.

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