When I set VueScan's "color balance" option to "none," the image is completely black. The best I can do to show you the nature of the image is
this photo, which was taken with my digital camera, holding the negative against a window. This is blurry and you can see shadows of trees within the negative area, but you can also see where the frame boundary is, as well as a hint of the image -- you can just make out the tree line that's clearly visible in the scan.
Descriptively, the negatives are darker than normal C-41 negatives, but they aren't completely black. I don't know how dark the base for this film was supposed to be, but assuming no darker than most C-41 films, there's substantial fogging going on. That could be age-related, though -- remember that this film is 16 years past date. The image density above that fog or color mask is very low. I don't have a densitometer, but I'd guess that the darkest parts of the negatives aren't as dense as the darkest parts of a C-41 negative with a good range of brightness recorded.
This particular frame was developed in NCF-41. This produced better results than the Svema formula with CD-4 substituted for CD-1. (I doubled the amount of CD-4 vs. what the formula specified for CD-1. This resulted in a developer with an amount of CD-4 that's similar to the amount of CD-4 in the conventional C-41 developer formulas that are available on the Internet -- 4.6 g/l of CD-4, to be precise.)
I'm thinking of trying a bleach-bypass process. My reasoning is that this might give a relatively good B&W image with just a hint of color.