Well, I did some research on that 4000 pixel count thing, and I heard that it’s actually 4000 X 4000 (after all, HD Video is 2,073,600 pixels per frame, or 1920 X 1080. All of my images are less than 4000 X 4000, so I don’t think that’s the problem.
As for compression, the first time through I saved the tiffs without compression, and I still ended up having issues. The picture below is what an uncompressed tiff looks like when I converted from jpeg to tiff (I had to convert it back to jpeg in order to post it on this board, but it looks the same.) The distorted bar on the bottom third of the picture is just one example of the type of distortion/artifacting that i’m encountering.

I have also tried saving the tiffs with compression, and while they come out clean (no artifacts visible in the still frame as pictured above), they still have artifacts show up when i put them in a video timeline. I’m beginning to think this is a timeline problem, but I pretty much have to keep my sequence settings as they are, because I’m using some video as well.