"Located in Chicago in early 1900's to appx 1970, Windsor Art Products produced reproductions of original art that they received rights to reproduce....thus it was a decorative arts publishing company. It had prints made and artists that gave proper brush strokes/etc by pressing or embossing to simulate an original. This was not done to deceive but to make art affordable to the general population. The main company (Illinois Moulding Company) framed the pieces and usually had gold/metal nameplates identifying the pieces. "
Also doubt it is tar. Tar doesn't stay firm and wouldn't be a suitable medium.. Many times oil paint is put on so thick it can appear to be tar!