Proclaimed as the “World’s most famous mixing bowl set,” the Primary Colors set was the first of the Pyrex items produced on white opal ware with colored overlay. The set included four mixing bowls, which came in yellow, green, red and blue.

The new Pyrex opal ware line was a result of a collaborative effort between Corning Glass Works and the United States government to create a sturdy, lightweight and unbreakable dish for soldiers during World War II.

A 1946 Ladies’ Home Journal advertisement touted the new opal ware bowls as “2 ½ times as strong as ordinary bowls,” “Heat resistant for oven use,” and used “For mixing, baking, serving and storing.”

As the earliest set released by Pyrex opal ware the new “Color Bowl Set” did not have standard model numbers such as 401, 402, 403 and 404 as we have come to know them today, but they are standard bowl sizes. Originally released with a more defined foot the bottom of the bowls was redesigned in 1950, creating the version of Pyrex opal ware bowls with which we are now familiar.

In 1947 the four-piece Primary Colors Refrigerator Set was released in yellow, blue and red. As the first Refrigerator Set the dishes included were the 1 ½ cup red (501) container, the 1 ½ pint blue container (502) and the 1 ½ quart yellow container (503). The earliest dishes in this set came with clear lids that had elevated lines along the lengths of the lid with a smooth section in the middle. In later editions the clear lids had elevated lines along the entirety of the underside of the lid while the top is smooth.