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what color space in Resolve for a film theatrical release ?


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#1 mailesan

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Posted 20 March 2018 - 12:54 AM

Hi.

 

I'm a novice at grading & it in need of some help. I recently shot my first film in Arri Alexa XT in Raw 2.8k. i graded the final film in DaVinci resolve for theatrical and my colorist told me the Rec709 Gamma 2.4 is a very good color space to work. so everything was Rec709 Gamma 2.4.( input color space/timeline color space/output color space).

 

Also i did small teaser grade of the same film in Baselight in P3 color space.  Teaser Below

 

 

Personally i felt P3 is much better compare to Rec709 in colors and black. i know that P3 color gamut is wider than Rec709. so here is my question .

 

 

1. Is Rec709 gamma 2.4 is good color space for theatrical release ?( input color space/timeline color space/output color space).

2. What is the correct workflow for film theatrical release?

3. This is my colorist workflow - Arriraw- Arri Raw to rec 709 lut then from here on rest of the grade. is this the right way? I felt that when you apply the Arri raw to rec709 LUT there is something wrong with image saturation and specially the black which becomes grainy even though I have shot with good exposure. 

 

 

I'm trying to figure out this for very long time so any kind of guides and advice will be great.

 

 

 

 


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#2 aapo lettinen

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Posted 20 March 2018 - 02:36 AM

It depends on which color spaces your monitor and projector can show in grading. If the monitor can only show rec709 then that is the preferred and also if the main release is tv rec709 formats. If your monitor and projector can show the P3 then for dcp release it is better to use p3 for viewing during the grade to see wider gamut... When rendering out you will convert the colours automatically or manually to dci xyz color space for jpeg2000 and it has benefits to have wider gamut originals. But if only having rec709 monitoring you will use that as a base and do the output conversion from 709 to xyz when rendering the jpeg2000 seq for dcp. The colour accuracy may be very good when doing the "low end dcp grade" in rec709 2.4 120cd and testing the brightness with rec709 2.4gamma 48cd/m2 calibrated extra monitor to simulate cinemascreen brightness, then using automatic conversion in resolve to output jpeg2000 sequence in xyz colour space and use other programs to wrap the jpeg2000 and audio tracks to dcp package
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#3 Bruce Greene

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Posted 20 March 2018 - 11:26 AM

Mailesan,  if your blacks look different between a rec709 grade and the p3 grade something is wrong.  And how are you viewing your results?  Do you have a p3 capable display calibrated to p3?  And if your blacks look different, your colors will look different also.

 

Basic advice:  If you don't have a p3 calibrated display, grade in REC709 and convert to p3 only when making a DCP for cinema projection.  This approach also has the advantage of using the same grade for web/tv deliverables.  If you grade in p3 you might need to re-grade somewhat for REC709 as the color space is a little smaller.  Nothing is lost going from a small space to a bigger space, but not the other way around.

 

And about the blacks becoming grainy using REC709?  ????  Not sure what's going on here.  I think you should set the Arri Raw converter to convert to Arri LogC, and then, in your grading stack apply the Arri LogC - REC709 LUT.  But this is if you are not using ACES in Resolve.  And Baselight has it's own color management system as well.

 

It seems you are using a colorist and not doing this work yourself.  At some point you need to either trust your colorist or find a new one.  If you are not a colorist yourself, trying to explain this stuff to you might be pointless.  There is enough confusion among colorists about color management, explaining it to non colorists can be quite difficult.  Users of photoshop have been discussing this stuff since the beginning and message boards on the web are full of confusing discussions full of mis-information.

 

I say this as the rare cinematographer who has been working as the colorist on his on films for 10 years.  I think I know this subject pretty well.  Since I don't have a DCI/p3 projector in my home, I grade on a REC709 Calibrated display in REC709 colorspace and convert to DCI/P3 for the DCP cinema deliveries.  The only downside is a very small loss of detail in the brightest and most saturated colors versus what could be seen if graded in P3.  Very few grades ever reach this level of saturation of bright colors though.  

 

And since your film has already been graded in REC709, all is done until the next movie!

 

PS. About the trailer you posted.  I'm viewing it on a REC709 display and all looks normal.  If it were in P3 it would look desaturated on my display.  Maybe it's been converted to REC709 for youtube streaming already?


Edited by Bruce Greene, 20 March 2018 - 11:32 AM.

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#4 mailesan

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Posted 20 March 2018 - 11:42 AM

It depends on which color spaces your monitor and projector can show in grading. If the monitor can only show rec709 then that is the preferred and also if the main release is tv rec709 formats. If your monitor and projector can show the P3 then for dcp release it is better to use p3 for viewing during the grade to see wider gamut... When rendering out you will convert the colours automatically or manually to dci xyz color space for jpeg2000 and it has benefits to have wider gamut originals. But if only having rec709 monitoring you will use that as a base and do the output conversion from 709 to xyz when rendering the jpeg2000 seq for dcp. The colour accuracy may be very good when doing the "low end dcp grade" in rec709 2.4 120cd and testing the brightness with rec709 2.4gamma 48cd/m2 calibrated extra monitor to simulate cinemascreen brightness, then using automatic conversion in resolve to output jpeg2000 sequence in xyz colour space and use other programs to wrap the jpeg2000 and audio tracks to dcp package

 

Thank you the reply. 


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#5 mailesan

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Posted 20 March 2018 - 12:09 PM

Mailesan,  if your blacks look different between a rec709 grade and the p3 grade something is wrong.  And how are you viewing your results?  Do you have a p3 capable display calibrated to p3?  And if your blacks look different, your colors will look different also.

 

 

Basic advice:  If you don't have a p3 calibrated display, grade in REC709 and convert to p3 only when making a DCP for cinema projection.  This approach also has the advantage of using the same grade for web/tv deliverables.  If you grade in p3 you might need to re-grade somewhat for REC709 as the color space is a little smaller.  Nothing is lost going from a small space to a bigger space, but not the other way around.

 

And about the blacks becoming grainy using REC709?  ????  Not sure what's going on here.  I think you should set the Arri Raw converter to convert to Arri LogC, and then, in your grading stack apply the Arri LogC - REC709 LUT.  But this is if you are not using ACES in Resolve.  And Baselight has it's own color management system as well.

 

It seems you are using a colorist and not doing this work yourself.  At some point you need to either trust your colorist or find a new one.  If you are not a colorist yourself, trying to explain this stuff to you might be pointless.  There is enough confusion among colorists about color management, explaining it to non colorists can be quite difficult.  Users of photoshop have been discussing this stuff since the beginning and message boards on the web are full of confusing discussions full of mis-information.

 

I say this as the rare cinematographer who has been working as the colorist on his on films for 10 years.  I think I know this subject pretty well.  Since I don't have a DCI/p3 projector in my home, I grade on a REC709 Calibrated display in REC709 colorspace and convert to DCI/P3 for the DCP cinema deliveries.  The only downside is a very small loss of detail in the brightest and most saturated colors versus what could be seen if graded in P3.  Very few grades ever reach this level of saturation of bright colors though.  

 

And since your film has already been graded in REC709, all is done until the next movie!

 

PS. About the trailer you posted.  I'm viewing it on a REC709 display and all looks normal.  If it were in P3 it would look desaturated on my display.  Maybe it's been converted to REC709 for youtube streaming already?

 

Dear Bruce,

 

firstly thank you for the reply.

 

I watched both the grade (Rec709 and P3 color space) in P3 projector and i noticed what i mentioned which is P3 color looks nice and Rec709 not that good. 

 

i'm not a colorist. sorry if i didn't mention in main post. I'm a DP and this is my first film so all this is very new to me so trying to understand how i can get the best possible image out of what i shot. What is  the correct work flow. coz i have seen what the image can look if done in the right way & also how bad it can look with the same footage. so next time i can be more careful before going into grade. 

 

Yes you are correct the teaser was graded in Baselight in P3 with cinema 4k projector and converted to Rec709 for youtube.. My main problem is that i was not lucky enough to do the entire project in baselight with proper cinema projector as my teaser coz of financial constraints and ended up grading in Davinci resolve with rec709 monitor. 

 

Is there a rule of thumb I should go by for future feature films?

 

Thank you once again. 

 

 

 


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#6 Bruce Greene

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Posted 20 March 2018 - 12:52 PM

 

Dear Bruce,

 

firstly thank you for the reply.

 

I watched both the grade (Rec709 and P3 color space) in P3 projector and i noticed what i mentioned which is P3 color looks nice and Rec709 not that good. 

 

i'm not a colorist. sorry if i didn't mention in main post. I'm a DP and this is my first film so all this is very new to me so trying to understand how i can get the best possible image out of what i shot. What is  the correct work flow. coz i have seen what the image can look if done in the right way & also how bad it can look with the same footage. so next time i can be more careful before going into grade. 

 

Yes you are correct the teaser was graded in Baselight in P3 with cinema 4k projector and converted to Rec709 for youtube.. My main problem is that i was not lucky enough to do the entire project in baselight with proper cinema projector as my teaser coz of financial constraints and ended up grading in Davinci resolve with rec709 monitor. 

 

Is there a rule of thumb I should go by for future feature films?

 

Thank you once again. 

 

 

 

I assume you saw the trailer only in P3 vs. REC709 on the same projector.  The contrast should look identical.  If it does not, something has gone wrong. Color balance should also look the same.  The differences should be subtle.

 

Rule of thumb:  Choose the best colorist and follow the workflow that they feel the most comfortable with.  When done correctly a REC709 grade should look identical after conversion to P3 and viewed on a P3 display.  So, if you like what you see in REC709, you will see the same image in P3.  The one difference is that the experience of projector vs. LCD or OLED display is different.


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