Alexa footage not correcting properly

[Gary Adcock]

Todd

if you have copies of the originals you should be able to match the images. if you are working from the H.264 files your ability to correct is limited.

take me through what you have and how it was shot?
my guess is that you are looking at original LogC footage and it looks flat and muddy.

gary adcock
Studio37

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

https://blogs.creativecow.net/24640

[Todd Heyman]

hi Gary..

i do have logC footage – it is apple pro res 4444..

it was shot in multiple conditions by a top notch DP that i often work with and one of the best crews in northern california.

having a few problems..
im having trouble keying footage (selecting certain colors) in my secondary and isolating that color and getting a nice smooth blur to correct that color. it always ends up looking like an impressionistic (seurat) painting or paint by numbers..

also having trouble maintaining sharpness and clarity

heres the rough cut with just nick shaw’s LUT before i removed it and started correcting.

https://dl.dropbox.com/u/2614696/Florastor_v2_noGFX1_logo.mov.zip

[Todd Heyman]

sorry, i forgot to mention, yes it started out flat and muddy, much like the onelight transfers I would get when I shot my spots on 35mm..(see Nike under SPOTS on the site below..we got a great color correct on that one)

i start with an autobalance in the primary room, then adjust till i get a decent primary correct. I then go into the secondaries and adjust lighting on the first few, then skintone, then any colors i want to isolate either by keying or adjusting the hue and saturation on that approximate color…

also i have a problem when i create a secondary with keyframes, i cant disable it or even reset it. it stays locked even if i choose reset all secondaries

thanks

todd
https://www.toddheymandirector.com/

[Oliver Peters]

Hi,

It’s hard to say what the issue is without a direct comparison, but you mentioned the keyframe problem, so I wonder if there’s some sort of larger Color issue. As far as better highlights and darks in the agency grade, it sounds like their colorist did some work in curves to dig out detail in these areas. The Alexa ProRes Log-C is pretty malleable, so you should be getting similar results to working with a one-light film transfer or RedLog from a Red One M-X. Of course, since you are comparing with an H264 file, this could also be “contaminated” by the way QuickTime player handles gammas. It might be helpful to post an uncorrected still frame and the corresponding frame from the agency grade, just to have a better idea of what can be done with the footage as is.

– Oliver

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

[Todd Heyman]

so oliver you havent heard of this locked secondary issue? color seems to be working in every other way..

im making a little headway with curves..ill see where that takes me..

[Oliver Peters]

Hi,

I just a quick test in Apple Color with some Alexa footage I have. If you add keyframes in the secondaries, that room is locked unless you first remove the keyframes. I believe that’s normal. In any case, there’s no problem in adding several keyframes and having the changes track accordingly from one keyframe to the next. You can enable and disable the room if there are no keyframes.

The keying issue you may be having is probably because of the Log-C profile. From what I can tell, the keyer is pulling the information out of the original media, not the corrected image coming out of the primary room. Again I think that’s normal. Since there is no proper LUT for the Alexa Log-C profile in Color, you simply don’t have very much saturation available from which to generate the key. That seems to be what’s going on.

– Oliver

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

[Fred Jodry]

Todd, Oliver`s last comment is the same as I think. However the paint by numbers quality you`re getting won`t improve mentionably with patching. It`ll just patch, and patch, and patch. Although you`ll have to re-do some steps to be sensible, haven`t you noticed that the best needed software at the moment is in the topic right before this one?

[Todd Heyman]

thanks Oliver..
i thought it was the keyframes and tried removing them but I couldnt find the in out points..ill figure it out. I think you’re right about it correcting from logC which limits saturation. I was told it had tremendous latitiude..how does it happen with 35mm film which essentially originates in the transfer process the same way.

Fred, I checked out the glue website..that seems like it would be a great tool..but wouldnt you have to remove that when heading to color like you do with Nick Shaws LUT…? again, how is 35mm handled

one stupid question..Im working in only one monitor but I’d like to see the viewer in a larger view for the details..is there a way to do this without setting it for dual display and moving them around to view..really hard to toggle while watching a full screen view..can only see partial image..

thanks for the info

[Oliver Peters]

[todd heyman] i thought it was the keyframes and tried removing them but I couldnt find the in out points.

You have to park on each keyframe and use the “remove keyframe” command.

[todd heyman] I was told it had tremendous latitiude..how does it happen with 35mm film which essentially originates in the transfer process the same way

You do have latitude, but it depends on from where the key is derived. It’s possible that DaVinci Resolve does this differently. Resolve uses both serial and parallel nodes (same as secondary rooms). As a test, you might try “backing-in” the Nick Shaw LUT with sat boost on and then see if that “backed” file gives you better results.

– Oliver

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

[Todd Heyman]

thanks oliver..

i asked nick about that and he pointed out this in his read me:

Important Note:
Since the plug-ins use 8-bit versions of the 16-bit LUTs supplied by ARRI, they are suitable only for previewing and for dailies/editorial use. They are not suitable for use as part of a finishing pipeline.