TIFF vs DNG workflow (Davinci vs Davinci+ACR)

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Adriano Castaldini

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TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostSat Apr 14, 2018 10:35 am

Hi everyone,
my workflow is Davinci-and-DNG based. The problem is that my footage is purple/green fringe affected, and Davinci hasn't a defringe option (there is a tutorial* showing a smart trick to reduce the fringe, but it's a sort of compromise), while ACR has a really good one and solves completely the problem.
Unfortunately, Davinci sees ACR-fixed-DNGs without the correction (i.e. fringe still visible), so the only way to benefit of the ACR defringe option is converting DNGs into TIFFs and then grading TIFFs in Davinci (instead of DNGs). This ACR-to-Davinci workflow has the advantage of being fringe-free, while the Davinci-solo workflow has the advantage of grading DNGs directly.
So, here is my question: RAW-tab a part, are there other clear andvantages in grading DNGs over TIFFs in Davinci? i.e. grading DNGs gives better results than grading TIFFs in Davinci?

Thanks in advance for your advices.

*) <https://vimeo.com/68459408>
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Hector Berrebi

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Re: TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostSat Apr 14, 2018 11:22 am

Adriano Castaldini wrote:So, here is my question: RAW-tab a part, are there other clear andvantages in grading DNGs over TIFFs in Davinci? i.e. grading DNGs gives better results than grading TIFFs in Davinci?

Thanks in advance for your advices.



Hey Adriano.

It seems in your case there are clear advantages to the TIFF workflow. You'll be loosing RAW functions, but considering you can apply a pretty good Onelight/Best Light correction in ACR, And keep it handy in case you run into a more difficult shot, there isn't much to loose in the first place.

On the other hand, TIFF may be bit harder on your media drives.. but definitely softer on your CPU. And it shouldn't loose quality over originals.
H e c t o r _ B e r r e b i
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Colorist ~ Consultant ~ Trainer
Da Vinci Resolve Certified Instructor
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Adriano Castaldini

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Re: TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostSat Apr 14, 2018 1:27 pm

Thank you for your fast reply Hector Berrebi!

So, if I understand correctly, the only/main advantage of grading DNG is the RAW-tab, right?
i.e. for all the rest of grading, TIFF and DNG are summary the same, is it so?
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Marc Wielage

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Re: TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostSun Apr 15, 2018 12:20 am

I just finished grading an entire 4.6K CinemaDNG 90-minute feature last night and saw no "fringing" per se. There were some normal noisy shots, due to issues with low-light performance and the Ursa Mini Pro chip, but we found that Neat Video got rid of 80% of it. We may do some tests to see if Resolve 15 NR can do an equally-good job in less time, since Neat rendering takes about 3fps on my system.

But no "purple/green fringing" per se. What monitor are you using for grading? Was it calibrated?
marc wielage, csi • VP/color & workflow • chroma | hollywood
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Dermot Shane

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Re: TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostSun Apr 15, 2018 4:23 pm

Adriano Castaldini wrote:Thank you for your fast reply Hector Berrebi!

So, if I understand correctly, the only/main advantage of grading DNG is the RAW-tab, right?
i.e. for all the rest of grading, TIFF and DNG are summary the same, is it so?


RAW presents to the system once debayered as virtual DPX in any case, so yea, aside from bakeing in the debayer settings (raw tab controls) there's nothing lost

if working in scene refered like some RCM settings or ACES just about everything that can be ajusted in raw tab is still avb, soft/sharp/scaleing and some camera specfic stuff will be locked in, but that's about it

in display refered workflow like YRGB you have to also lock in the gamma / gammut / exposure / white ballance when you render the transcodes, but if hte cam orig is nearby then this should not be a huge concern
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Adriano Castaldini

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Re: TIFF vs DNG workflow (Davinci vs Davinci+ACR)

PostMon Apr 16, 2018 5:50 am

Dermot Shane wrote:if working in scene refered like some RCM settings or ACES just about everything that can be ajusted in raw tab is still avb, soft/sharp/scaleing and some camera specfic stuff will be locked in, but that's about it

in display refered workflow like YRGB you have to also lock in the gamma / gammut / exposure / white ballance when you render the transcodes, but if hte cam orig is nearby then this should not be a huge concern
Thanks Dermot Shane for these useful advices!

Anyway, I think (I hope...) I solved it.
First of all, the fringe in my case is mainly lateral chromatic aberration caused probably by various things: anti-aliasing filter in camera, lens (Tamron 24-70), filter (Hoya UV), etc. and it's visible in highlights/contrast edges.
ACR manual Defringe is fanstastic and does perfectly the job, so one workflow could be DNG-to-TIFF (ACR with manual Defringe), then grading TIFFs in Davinci (but losing RAW tab).
At this point the question: what is better, losing RAW tab for working with perfect TIFFs, or trying to solve the fringe directly in Davinci and enjoy the flexibility of Raw tab?
As I wrote, Nick Driftwood method works but in my opinion is not clean actually.
So I tried to find another node-only-based solution that's the following:
1. Splitter/Combiner: Green with just little luma denoise (3 in my case), Red and Blue a bit more (5 and 6);
2. A node after the combiner has saturation 0 and a very little sharpness (0.48), then it ends to a Layer Mixer;
3. Restarting from the source, a node isolates the fringe color (Qualifier) and desaturates it (in comb with Hue);
4. After this, another node with Gain 0.01 and a good point of blur (0.6) that ends to the Layer Mixer (2nd input);
5. After the Layer Mixer one last node with denoise (in my case Luma 2 and Chroma 10).
Basically this method mainly adds Qualifier (and noise reduction) to the old Nick D. method.
The result seems to be very near to the ACR quality (and I can still use Raw tab!)
I hope this could help someone else with my issue :)

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