Test footage shot by Frank Sauer and Andrew Reid
Something I have discovered while editing all this GH4 4K material is that the 8bit codec Panasonic uses is quite complex and requires more power than ProRes. I have also found that the sequence settings and video proxy settings in Premiere are a good thing to pay attention to this time… the default ones no longer cut it.
Along the way I have found a few tricks to get the colours in GH4 footage to absolutely sing with Film Convert and Premiere using the Alexa Rec 709 profile.
4K from the Panasonic GH4 grades amazingly well. Normally I like to use Film Convert to give quick ‘looks’ to my footage. I much prefer this to twiddling with colour wheels all day in Resolve. However there’s no profile for GH4 material yet, so it requires some special sauce to get it to work properly.
The key is to find the non-GH4 camera profile that gives you proper colour saturation, proper colour temperature and doesn’t crush the blacks or burn the highlights too much.
It turns out that camera profile is the Arri Alexa in Rec.709!
This tells you a lot about the quality of the GH4’s source files that it matches so well to this preset. I tried all the DSLR ones and this one worked out best. The CineLikeD profile on the GH4 is somewhere between Technicolor CineStyle on the 5D Mark III and Cinema Gamma mode on the GH2 in terms of the curve and colour response, but there’s FAR more data in the file.
Most of the profiles, BMCC Video for example give the GH4 footage a bit of a magenta bias which I didn’t like. You can use the colour wheels in Film Convert to compensate for this but this to me didn’t feel right, like something was mismatched.
With the Arri Alexa Rec 709 profile, the colour seems most loyal to the film stocks and the shadows don’t get crushed to death. White balance works about how it should and you can do further fine tuning with the other controls. Saturation is spot on at 100% but sometimes benefits from a slight increase to around 110-120% depending on the shot. I turned Film Grain off (0%) as I like how clean and silky smooth the image is at low ISOs on the GH4.
Sequence settings, video previews and proxies
In the Premiere Pro CC sequence settings (don’t use FCPX), you need to be careful. I’ve had Film Convert corrupt the GH4’s 4K image on default settings. The Video Previews are set to 1080p i-Frame MPEG by default. This is where I get the corruption. Film Convert is also very slow to render on the CPU. So first change this in the effect pane for FilmConvert, selecting GPU rendering.
You can further increase performance and maintain 4K playback after rendering by setting the video previews for your sequence to Quicktime with ProRes 422 HQ as the codec. Be sure to enter 4096 x 2160 for the resolution if you shot in 4K DCI mode on the GH4. If you shot in Ultra HD mode enter 3840 x 2160. The default is 1920 x 1080 even if your timeline was set to 4K.
Now render the clip on the timeline with Film Convert on it and you will see it fly through 10x faster than on default settings. The advantage of having 4K preview files is you can full screen the monitor on a 2.5K iMac and it will look much sharper than 1080p. You can also zoom into 100% in the monitor preview and check focus or fine details. Just be sure to have plenty of drive space for the 4K ProRes video previews.
2K delivery?
For the best looking 10bit 2K with 4444 sampling I recommend to do all your grading work in 4K, then deliver as 2K with the export feature in Premiere. Export to 10bit 4444 ProRes to allow the file to maintain all that colour information. Essentially you are squeezing that 8bit 4K image into a 10bit 2K file. 8bit 4K has 4x the data of 8bit 1080p so converting it to 8bit 1080p will throw away too much.
