ASC CDL worflow with the Alexa camera

[Oliver Peters]

One possible solution is Red Giant Software’s new free LUT Buddy. This allows you to read a LUT in certain formats and then apply that in apps like FCP and After Effects. It does this by applying an instance of LUT Buddy as a filter and then reading the LUT profile. I’m not 100% sure whether it can take any LUT or has to be used at the creation end as well, but it’s worth a try.

– Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com

[Jonathan Holm]

Hi guys,

Thanks again for all your help.

I just downloaded the Nick Shaw plugin demo and it looks like it is reading the LUTs properly. Does it automatically read the LUT files that are in the same folder and apply the color correction to the clips? I can’t tell if it is reading the LUT file or if the plugin is just doing a general color correction.

Also, is there a technical reason we can’t finish with the Shaw plugin? Our post budget does not allow us to go to a big color correction house, and we are doing a lot of after effects work so we need to have the LUTs applied before we send the clips to our graphics guy.

Thank you everyone, you’re all a huge help.

[Oliver Peters]

[Jonathan Holm] ” Does it automatically read the LUT files that are in the same folder and apply the color correction to the clips?”

I believe these are just default settings. His plug-in uses his own curve values reverse-engineered from ARRI’s log-C to 709 corrections.

[Jonathan Holm] “Also, is there a technical reason we can’t finish with the Shaw plugin?”

He is processing in 8-bit and therefore considers these for dailies only. 10-bit values would be better. You may get some banding in gradients like skies. OTOH most of your footage will likely look OK.

– Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com

[Jonathan Holm]

“I believe these are just default settings. His plug-in uses his own curve values reverse-engineered from ARRI’s log-C to 709 corrections.”

So does that mean it is not reading the LUT file? After I apply the Nick Shaw filter, the color timing looks pretty close to what the DP wanted (he sent us bitmaps of the images with the color timing information). How is it so accurate without actually reading the LUT file?

“He is processing in 8-bit and therefore considers these for dailies only. 10-bit values would be better. You may get some banding in gradients like skies. OTOH most of your footage will likely look OK.”

So does that mean the quality of the footage is degraded?

Thanks again for your help.

[Oliver Peters]

[Jonathan Holm] “So does that mean it is not reading the LUT file?”

I don’t believe it does. They happen to be the same adjustments.

[Jonathan Holm] “So does that mean the quality of the footage is degraded?”

Technically yes. The difference between 8-bit and 10-bit.

– Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com

[Jonathan Holm]

Great, thank you. This is not going on the big screen, so I think we’ll be fine using 8 bit over 10 bit and making slight adjustments to get the color correction exactly right. Going to download the full Nick Shaw plugin and use that.

Thanks again for all your help everyone!

Jonathan

[Jonathan Holm]

Just FYI I tried the Red Giant plugin as a quick test before buying the Nick Shaw one, and it can’t read the cdl format.

Also, responding to Todd’s post earlier, I totally agree more communication was necessary. Unfortunately we were told about the specs only a few hours before they shot it so that’s why we’re dealing with it now. Looks like we may have a workable solution though.

[Oliver Peters]

[Jonathan Holm] “Just FYI I tried the Red Giant plugin as a quick test before buying the Nick Shaw one, and it can’t read the cdl format.”

Correct. Colorista Free would allow you to manually enter CDL values, but it can’t read an external list. LUT Buddy would read a LUT file in one of several color profile formats, like .icc. A CDL is a text file, just like an EDL.

– Oliver

Oliver Peters Post Production Services, LLC
Orlando, FL
http://www.oliverpeters.com

[Mike Most]

I would humbly point out that any competent colorist should be able to come up with something that matches your original intent directly from the original LogC file using your dailies as a reference very quickly. Using your original LUT will only tie their hands in terms of both range and ability to come up with a “cleaner” version of what you originally intended. A lot of producers, studio people, and even cameramen seem to think that passing on LUTs to the final colorist is a time saver, but as an experienced colorist, I can honestly tell you that it’s not. It’s one of those things that sounds good, but is usually thrown out by the colorist in favor of a new correction that implements the original intent, but in a better way. Where LUTs are handy is during editorial and/or visual effects work, so that both the editor and the VFX artist can look at the material through the LUT and know what is intended in the final version. But for final color, it’s not nearly as useful as many people seem to think, even when it works.

[Gary Adcock]

[Oliver Peters] “I believe these are just default settings. His plug-in uses his own curve values reverse-engineered from ARRI’s log-C to 709 corrections.”

That is correct, as would be almost all color correction done in RT within FCP, it is also my understanding that there is a large amount of clipping and clamping in the Shaw filter profile to achieve something close to what a real LUT workflow should be, its not just about the color denisity its about adjusting of the gamma of an image heavily weighted in the shadow areas without clipping the highlights.

I use the GlueTools Arriraw converter that also allows for implementing CDL or other 3D LUTs on import when using an Alexa ProRes file recorded in LogC, it was built as part of the offline/ online processing to use Arriraw but as an aside it does allow for a real LUT to be used within FCP.

gary adcock
Studio37

Post and Production Workflow Consultant
Production and Post Stereographer
Chicago, IL

https://blogs.creativecow.net/24640