DescriptionLate 1930s era bubbler sign for "PITTSBURGH PAINTS" has multi-colored individual letters, mounted on metal retainer with reverse screen-printed glass face reading, "Smooth as Glass - Wallhide - Florhide - Waterspar - Sun-proof."  It is very collectible due to its being multi-colored since most bubbler signs were single colored.  The bubbling effect was also utilized in Christmas tree lights from the 1930s through the early 1950s.