There were 2 processes in distributing film. The first is chemically developed film. The second is printed film.
Chemical developed film uses the master negative (usually referred to as the o-neg) to create a limited number of interpositive prints. This is pretty much the last the stage that the production team/studio have any say in the matter. The negative is color timed to create the interpositives and then the distribution company uses the interpositives to create a set of internegatives that are used to create the final film prints. Other than color interpositives having a tint (which I believes aids with the whole chemical duplication process) they are the best source for correctly color timed images. There is no guarantee that any of the internegatives or the final prints aren't a bit off in color. If the o-neg still exists and is in good shape, it still needs the correct color timing. That data can be recorded but the interpositive can also be used to recover that information.
Technicolor is the best example of printed film. Originally they used 3 separate negatives, one for each color, but it can be derived from color film as well. Again, you have to start with the o-neg and create a color timed master. As this is a printing process, it requires a master for each color. These are called the separation masters. Using a chemical process, the masters are used to create the print masters. What it amounts to is that the process pits the film. The more color, the deeper the pit. In the printing process, the pit is filled with gel ink in cyan, magenta, and yellow, and transferred onto the final print. When the gel ink dries, it flattens out and leaves the final print smooth. It also creates some inherent alignment issues.
So no matter the movie, the best source is the o-neg properly timed and the next best source is an interpostive of the color separation master. In some cases, they have used part of the o-neg and part of the separation master, usually retrieving the cyan and magenta from the o-neg and the yellow from the separation master. They have a new all digital technicolor restoration process that aligns the separate colors and produces a truly outstanding picture that is clearer than any techincolor IB print ever was.
So whether it is a chemically developed print or a technicolor IB print, it is sufficiently removed enough from the work of the production team and is prone to enough errors in production that it doesn't represent the best source to retrieve a film from. For the DVD market and earlier, they often did use prints (cheaper and easier than going to the effort to do a restoration on the negative), but with the advent of HD and Blu-ray, the clarity called for calls for doing a proper job from the best source material available. In some cases we have what we have. Citizen Kane was restored from a print because the negative was lost, but in the case of most modern films, that will produce an inferior product. HD still isn't high enough quality that the majority of film making slight of hand is revealed.