Frame Rates 23.976 vs 29.976

it's my understanding as an editor, that for commercial broadcast spots, your best bet is to shoot the ad at 29.976 fps, since in the end we need to deliver the finished spot to the TV stations at 29.976 fps anyways

You shoot int he frame rate that supports the look you want.

The creative director here, prefers to shoot our spots at 23.976 fps, mainly because he feels like it gives it a more cinematic look

The creative director is right, 24 has a specific look that can be very appealing.

All you need to do is to do what has been done for 60 years, add frames to make 23.98  29.97, this is called 3:2 pull down. Look up 3:2 pull down and you will find a bunch of information. Most software will do this automatically if the project clip is 23.98 and the output is 29.97.

For what it's worth, I've always felt that film as a medium for acquiring a moving image is what makes images shown in rapid sucession look like film, not frame rate.  Now that just about everything is video, it's gamma curves and grain filters that mimic film.

Back in the early 1900s, film was recorded by a film camera that was hand cranked and viewed on a kinescope that was also hand cranked.  If the filming or playback sped up or sped down, it still looked like film because it was film.

And film transferred to video will still look like film, regardless of frame rate.

The video look that many dislike (but several have become accustomed to) is not a direct result of frame rate, but rather video being a different medium entirely (both in it's prior analog version and current digital version).

Video has gotten significantly better at looking like film (being progressive instead of interlaced was a huge step as well), but frame rate isn't what makes that happen.

I've been trying to convert a tv spot from 23.976FPS to 29.97FPS for broadcast. I simply bring the 23.976 video file (created in After Effects) into a 29.97 timeline in Premiere. It seems to add pulldown correctly, and plays back correctly on my broadcast monitor. I then export the file in Adobe Media Encoder as a 29.97 file, interlaced, upper field first.

HOWEVER, when I sent this spot to Spectrum, the spot played horribly on tv. It looked like it would if you play the file on a progressive computer monitor. I have researched this, and can not figure out what else I should be doing for this conversion.

Am I making the video file the wrong way in After Effects? Any ideas?

24p will look more "professional", more "cinematic" than 30i, all else being equal.  3:2 pulldown can easily take the footage to the broadcast standard, but if you shoot at 30i, you're losing that special "film look" and can't easily get it back.

I think you're creative director is right.

The "cinematic look" is, in reality, more blurriness as either the camera pans or subjects move. I'm in my 60's, so not a digital baby by any means (as in, born in the digital age ... ) ... and sitting in "cinemas" watching blurry pans and movement was always an irritant for me. I prefer the 29.976 shooting speed ... as, in blind tests that have been run, the vast majority of people viewing modern content.

Your Creative Director may have Delusions of Cinematic Grandeur ... just, as a possibility. Your audience doesn't.

Neil

IMO more frames are always better (smoother in action and movements...)

you should always be able to go back to 23.976.