Originally Posted by Ed Sukach
Ed, the yellow color to the negative is due to color masking, not an intent to offset color balance to eliminate cyan filtration (although it has that side effect).
This mask corrects color and eliminates the impurities introduced by the organic dyes used. That mask is tailored specifically for each film and therefore the yellowish orange cast will vary as will the relative speeds of the 3 color layers to balance the film.
The cyan, magenta, and yellow dye densities over and above that mask should be 'normal' and balanced in a neutral and therefore looking at a neutral image you should see a neutral spot, not a colored spot. So by examining a negative you would be able to judge whether a given dye is lacking.
You are correct in that a tungsten film under the wrong illuminant would do as you say, but there are few tungsten balance negative films available today. Of course that is not ruled out until it is checked.