Export Settings for Film Festival

Okay, so this will probably be my least coherent post yet as this is an area where I am probably the least knowledgeable

We are exporting our latest short for a friends & family film screening we are doing and I want to make sure our settings are accurate

The last two shorts we shot on the BMMCC OG were colored/edited without us so we weren’t part of this final process

For reference, we are working on a Mac, and used the superscale feature on all of the clips

What is confusing me now is Rec709 vs Rec709a and really just what the settings should look like in general

I do know that the first time we exported we used h.264 which obviously caused banding and the last time we did ProRes 444

Thank you for any help, hope this made sense!

Grading with Rec.709-A as an output color space setting is most often used for a specific (and not really recommended) case — grading in Resolve on macOS by viewing only the GUI viewer image on an Apple display in its default mode as reference, with the preference setting for "use Mac display profiles" engaged, and the intended delivery is to match that GUI image exactly in YouTube/Vimeo (or similar online video platform) on Apple device displays. There is an additional use case for it with current MacBook Pros or Apple's external XDR display set to BT.1886 reference mode, but using a dedicated BT.1886 calibrated reference display connected via SDI is a much safer bet than relying on the OS level color management for BT.1886 reference.

If you're referring only to the gamma tag option in the "advanced" options on the deliver page, there is no difference between choosing Rec709 vs Rec709-A. Both options yield an NCLC metadata value of "1" for the transfer function. The gamma tag option has no impact on the image data. It only controls the NCLC metadata tagging on the file.

Details of your Resolve project's color settings while grading, reference monitor spec, along with the specs of the display setup for your screening would be needed to be able to give advice about how to create the right deliverable file.