I am wondering if this is IB Tech with the gray soundtrack?
No stock markings detected, and color is quite nice. Any ideas?

Have you checked out Paul Ivester's site, that has a section on soundtracks. http://www.paulivester.com/films/filmstock/guide.htm

Robert,
Thanks for the reminder about Ivester's site which is a great reference for many things film related.
Here is an image taken from his web site (http://www.paulivester.com/films/filmstock/guide.htm)


It seems like Paul's example is very comparable to the Fudd cartoon image in previous post. So maybe my cartoon is in fact the "Clear Edge Double Rank Technicolor" IB Tech....

One way to check genuine IB Tech is to hold the emulsion uppermost and move it about under a bright light.
If it's genuine you will be able to see the build-up of the thick three emulsion dye layers.
Also, old IB Tech often has a slightly warped first hundred feet or so.

Your variable area optical track looks like a recent digital produced one with uniform recurrent spikes looking like a neat graph. Original analogue mirror-galvanometer exposed sound tracks look different. So less likely to be IB Tech in the digital era ?

As I understand it, with IB Tech, the optical sound track was processed separately as black and white so it looks grey to the eye. But there were also blue track IB Tech prints. But they were the same colour blue you can see above in the Reel Magic header.

Ian