Some best common practice DCP color space workflows part 2
How to make 3D LUTs in Nuke PLE
Color Space (Wikipedia)
3D LUT (Wikipedia)
“Color and Mastering for Digital Cinema” has some examples of DCP color space workflows:
Glenn Kennel says in “Color and Mastering for Digital Cinema” that the standard DCP workflow (in 2004) is to retain the film look on the digital version of the film instead of using brighter colors that are only possible with digital cinema. A similar 3D lookup table (film stock emulation 3D LUT) that was used to grade the film on a P3 projector can be used when making the DCP.
Arri Alexa whitepaper:
Arri has some suggestions for color space workflows using their Alexa Digital Video Camera. They suggest you can use a bleach bypass 3D LUT on dailies if that is the look you intend to use on the final product.
Some thoughts on low budget DCP color space workflows:
In “Color and Mastering for Digital Cinema” the author explains how the 2.6 gamma 12 bit, DCI XYZ color space standard of DCPs was made for the standard Digital Intermediate workflow of 2004 which uses P3 projectors for grading.
Now you have more options when choosing a workflow: You can use filmconvert and 3D LUTs with software like Fraunhofer Easydcp +, After Effects, Nuke, and Davinci Resolve.
It is now cheaper to use similar workflows to the ones big-budget productions used in 2004. But big-budget post-production workflows have access to a P3 reference grading projector.
This is still expensive.
Even if low budget productions intend to directly convert to DCI XYZ from Rec 709 and retain its white point, color space and gamma the greys would seem darker and your picture seems more washed out because of less luminance (14 Fl) in the cinema than on your monitor. A computer monitor or TV could have double the luminance of cinema projection. That is why what could look like a film look on your monitor could look less like film when watched in the cinema.
In the Alexa white paper, they suggested watching material shot with the Alexa with a bleach bypass LUT and this attraction to the look from 35 mm seems to be common in DCP color space workflows.
This attraction to the look of 35 mm is also seen in the choice of using film camera optics with ND filters to get a shallow depth of view in low-budget films.
For a good-looking DCP that looks more like Hollywood films shot on expensive cameras and graded on p3 projectors, it seems low-budget filmmakers should also try to mimic the projector-based grading workflow.
Even though they can not afford to view the material in the full dynamics of 12 bit or in P3 color space, a projector that is calibrated for 14 Fl could help.
Using first a 3D LUT from LOG to rec709 on a cheaper rec709 projector and then later using a 3D LUT from LOG to P3 on a more expensive P3 projector could be an option.
The future of DCP color space workflows may be brighter colors and cooler white, even though most workflows now mimic the look and feel of the less bright colors and warmer white of 35 mm projection.
4 thoughts on “Some best common practice DCP color space workflows part 1”
thanks for all the valuable info you are sharing on your blog.
I baked a DCP for a festival from an HD stereoscopic movie. Problem is, we graded it relying on our panasonic HD monitor (REC709). Since stereoscopic DCPs are projected at a very low brightness (3.5-5.5 FL vs. 14fl of the 2d movies) the picture looks really darker (and more darkened by wearing the active shutter glasses).
We use apple color for grading (switching to resolve in the near future). Is there a way to grade emulating (something close I mean) that kind of brightness without using a projector?
Normally at exibitions we screen 3d movies using normal projectors and blu rays in sync.
So if I understand well, we need to do 2 different color grading, one for DCP delivery (more brightness, gamma etc…) and one for standard projection?
I’m so confused at this point!
thanks in advance.
You could make or have a viewing LUT that simulates 3.5 ftl. But I am not sure how you would do it perfectly, I think you should at least use projection to try to emulate the effects of wheel/filter and glasses. Perhaps a ND filter on the projector and glasses with similar ND like properties as 3D glasses. It is difficult to simulate a dark room with silver screen (RealD, MasterImage), If you do the grade in a calibrated cinema you could see how it looks with fallout of light at the sides of the screen, and if you move to seats at the sides you could see how it would look with 1.5 – 2. ftl. If you watch movies like Transformers 3 in 3D it seems they have a lot more of the information near 100 in a 0-100 Color RGB Parade scope than a normal 14 ftl grade. I think they also did a special 6 ftl grade for some cinemas, 3.5 ftl is not ideal.
Where can I get a good .3dl P3 to XYZ LUT?