I just noticed that in some shots my highlights are blown out. I have to assign a Levels-effect with "Output White" set to something 0,8 to get rid of the blown out highlights.
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You can download appropriate viewing LUTs for Alexa LogC from Arri's web
site. These can be applied to your footage using the LUT effect.
LogC is its own unique curve and color space, so you need to use the
right tools for it, not try to apply something built for other spaces.
nice! That seems to do the trick for me when viewing in AE. But here's the tricky part:
I need to do my compositing mixing Alexa footage and other RGB-files. So - in the end I'm gonna need a logarithmic DPX-sequence for colorgrading in Autodesk Lustre. How do I render in Log? Deactivating the LUT effect on Alexa clips? But what about the RGB images? And what colorspace do I select in the output module? Do I need some kind of reverse-LUT for this? I don't know any place to provide a LUT for rendering.
(argh...this stuff is confusing!)
If you've got a mix of formats, it's best to convert things into one
common format. You can use a LUT to convert the Alexa footage from LogC
to linear, then apply the Cineon effect to convert that linear to log
and render the results out as log DPX.
Now everything is in log and you can composite and render to your
heart's content. Or convert the Arri footage to Rec709, do your
compositing in that space, then convert to log for your final DPX render.
But you'll want to do a lot of testing to make sure you're not losing
color accuracy or clipping highlights with all that conversion. Working
in Rec709 is easiest, but it's a more limiting color space.
You might want to visit the CineTechnica blog and read some of their articles on Log color. It's a good place to start. There are also many discussions on log color workflow on the Red forums.
Then you'll want to work out a production workflow that fits your project and make sure that everyone from the DP to the final Color Grader is on board. It's critical to have all of this worked out before you start building things that fall apart downstream.