I'm stabilizing 3840x2160 CF RAW files in AE CS5. I, of course, then choose the 1920x1080 final framing that I want from that original large frame for output as a Cineform avi for Premiere.

These files have had a simple LUT applied to them for editing, but real color correction is going to happen by a pro in the online studio.

My question is what bit depth should I output these clips from AE with? Should they be 32bit...or 16 or 8?

Any thoughts appreciated.

definitely not 8....

sending it to a colorist, you should at least have 10 bit color...

you should have your comp set to either 32 or 16bit...I would just go 32 myself
and keep in mind whatever effects you apply work in 32bit....if it's just a stabilize and crop you should be ok...if you have one 8 bit effect applied then its all 8bit processing for that clip

you can work with the comp at 8bit and then change it to 32 before render to speed up workflow if you like

MIke, thanks for the reply. That's pretty much what I had assumed, but I've been tripping over my assumptions quite a bit lately and it's nice to be able to get a little bit of insurance.

You might want to put a small amount of video on the timeline at 16bit and then flip the project to 32bit... I don't think you'll like what you see... 16bit for video, 32 for comps??