A "Phostint" card from Detroit Publishing Co. The DPC was the only American company to license the Swiss photochrom
process, which they would eventually register in 1907 under the name Phostint. Based on the number of this card (10037), it was published between 1906-1907 but is postally unused.
Although the photo doesn't convey it, I'm sure that copper pouring was not only a strenuous job but a hot one too.
