Alexa 35 Anamorphic Editing

I'm working with the Alexa 35 on a feature that is being edited in Davinci Resolve and I'm getting some unexpected results that I'm hoping you all may have some insight into.

I'm in Resolve 18.6 on an M1 Macbook Pro running Sonoma 14.2.1 and on the Alexa we're shooting Open Gate 4.6k with a 2x anamorphic desqueeze. When loading the footage into Resolve the 2x desqueeze is handled properly and the footage looks great. My understanding is the anamorphic file should retain it's vertical resolution of 3164 but double the horizontal resolution. However when I load the footage in a timeline with a square pixel ratio of 9216x3164 the file is half the size.

When I load the same footage into Premiere with a 9216x3164 sequence it fills the frame. Anyone have any ideas of what might be the issue in Resolve?

Thanks

It's anamorphic so the pixels are no longer 'square' would be my guess. If you can supply a frame grab or clip, I could have a look.

However when I load the footage in a timeline with a square pixel ratio of 9216x3164 the file is half the size.

Crazy question: why are you working in 9K? Uprezzing the material will not yield any picture quality improvements (at least to me) -- I don't see this as a good workflow at all.

Scope deliverables are 4096x1716 (theatrical) or 3840x1607 (streaming/home video), and those are legitimate aspect ratios. To me, doubling these numbers would simply make the system work twice as hard with no actual improvement in picture quality.

Worst case: call Arri and ask to speak to a workflow specialist. They can give you real-world advice compatible with whatever systems you're using:

Arri Americas
3700 Vanowen Street
Burbank, CA 91505
(818) 841-7070

Crazy question: why are you working in 9K? Uprezzing the material will not yield any picture quality improvements (at least to me) -- I don't see this as a good workflow at all.

Yes exactly Marc, and then trying to fit a square pixel, that now has an aspect ratio. into a wide 'round' hole; as I say my guess> 4K DCI project; non-square Aspect ratio 2:1; would be what I'd try, Andrew.

BTW saw you in that video with the very nice Darren Moyston; very cool sir!

Thanks for the replies guys. I understand the issues with the anamorphic de-squeeze. I'm not concerned about the horizontal resolution. My only concern is that Resolve is showing half the vertical resolution of 1582 instead of the 3164 that it's originally shot in. This may become even slightly more of an issue because we're cropping in slightly due to the lens not quite covering the open gate sensor so I don't want to lose even more vertical resolution.

In my mind the footage in Resolve should show the same resolution as in Premiere/Finder/Arri software of 4608x3164 (2.0) Not 4608x1582(2.0) as it's showing in Resolve.

Can you post a short sample to a cloud service to look at?
I have used Red anamorphic stuff in the past and it scaled correctly.