Possible artefacts in Resolve

colorcorrection
workflow
Tags: #<Tag:0x00007f3c6124b428> #<Tag:0x00007f3c6124b158>

(Margus Voll) #1

Hi.

I wonder how to diagnose any errors that i may get while grading. What i mean i just had commercial where one shot had some super strong solarisation and i had to fall back from Alexa ITT profile to rec before my timeline.

Could it be that REC display chain is not seeing the details and will have issues or
is it possible the issue is in material?

It was shot on Alexa.


(Francesco Luigi Giardiello) #2

Hi Margus,
are you talking about on set grading, through a SDI feed?

Best,
Francesco


(Margus Voll) #3

I talk about final grading in resolve in ACES cc and rec709 display. I’m not sure yet if it is in transform or in my monitoring.

I could provide a part of original footage and results that I see.


(Margus Voll) #4

What happens is that some times one channel is broken and i have to dial it down a lot.

I was wondering if that is caused by to much data for Resolve Alexa input and REC 709 to display transforms or is this any other issue?

I attached screenshots: original (Arri input transform, REC 709 display transform) original scopes, dialled down image, dialled down scopes.

Here are some screenshots and i tried to mark the issue areas with green freehand drawing.


(Scott Dyer) #5

Margus,

This looks to me like the same issue discussed here: Colour artefacts or breakup using ACES

Would you be able to provide me with an ACES OpenEXR or camera original crop of just the problem area (square crop around that LED ring) that I might be able to use with some other examples I have accumulated to make a definitive post on this issue?

And to any others who have encountered this issue, if you also have examples where bright blues clip out, I’d be keen to examine those as well. Please post here or send to acessupport@oscars.org if you are able.

Thanks.


(Dermot Shane) #6

i can send you a fine selection, ArriRAW and ProRez, but due to actor’s contracts not a frame of it can be shown in the wild


(Margus Voll) #7

I just 10 minutes after posting my example got to the other thread. It seems to solve my issue for now.

I can send this shot and another job i had as an example.
I will see how would cropping work.

I could send the full frame for sure, both jobs were shot on Alexa if i’m remembering it correctly.

I have seen now something interesting also with dark areas of image. Maybe it is just my monitoring but i will dig a bit more and if it is not monitoring i will let you know.


(Scott Dyer) #8

@dermot.shane being able to sample the values in any problem image would still be useful. I will not repost or share the image in any public forum (but will use the RGB values from the offending areas on illustrative plots - no pictorial context).

@Margus_Voll this shot and any others you have would be tremendously useful. I can perform cropping to the region of interest if that is an issue. Please let me know if there are any rights/permission restrictions about reposting crops of the frame as pictorial examples.

At your convenience, please send files or links to download the files to acessupport@oscars.org . And please remind me in the email if there are usage rights/permissions to respect. Thanks!


(Margus Voll) #9

Just sent some link over email. Lets hope i did the files correctly.