This may not be the proper place for this but the moderator can change it.
Has Anyone done research into the companies that manufactured colored glass rods and cups and supplied to other glass manufacturers all over the world? I.E. Reichenbach Farbglasshute, Kugler, Schuster & Wilhemy, etc. Some of these go back to almost the mid 19th century. I am interested to see if anyone has been able to establish the exact colors they were producing and where their customers were. We normally try to establish the maker of an item by it's color, but if numerous companies were buying their color from the same supplier then they would have the exact same colors and could add to the confusion. I know there are about 4-6 companies at present that produce soda lime glass this way and ship all over the world and several others that make just numerous colors in borosilicate.
Schuster & Wilhemy list several "chemists" on their website that were evidently responsible for many of their color formulas. I think some of these ended up forming their own companies or working for many other companies. The "trail" would be very interesting if any info still exists on this subject.