Hi,
Modern fired enamel (as opposed to lacquer enamel, which is not really enamel in the classical sense at all; this has been misleadingly coined "cold enamel" by the mighty PR marketing machine. Again, this is NOT enamel in the classical, collector's sense!) is a far cry from classical fired enamel from the golden age (pre-1950's) due to restrictions on "dirty" or "dangerous" elements used in the production of fired enamel.
If you look at modern enamel dials under a 4x (or better yet, 10x) loupe, you will see immediately what I mean - pits, uneven surfaces, uneven colors and lettering, etc.
This is a function of both the prohibition against using previously mentioned "toxic elements" and the prohibitive cost of labour to do the job properly - multiple treatments, firings, sanding and refiring, etc.
Jaquet Droz seems to have the most consistent quality of fired enamel dials in the modern era, followed by Breguet.
As much as I love the Lange Anniversary, the quality of the enamel dial would be considered medium grade, at best, in the pre-1950's era.
Again, look at the surface - pitting, evenness, etc; look at the colors.
Cheers,
TM