Yes, at least the enamels for colouring, US too, have a look in the 1911 French global trade directory in the Glass-study, pages 111-113 ÉMAUX (FABR. D), ENAMEL (MFRS. OF) — GLASUR — ESMALTES — SMALTI. Interesting that most of the US makers were base in Providence RI. As many in the US as in UK and Germany. But then it was a French directory so not as comprehensive for the rest of the world. Even lists 1 in Japan.