Here’s an example of how ads can aid in researching an item. A few years ago a friend of mine was trying to piece together a biography of Louella Ballerino, when I ran across this ad featuring her working in Bates fabrics, making swimwear for Jantzen. Not long after that I found the swimsuit below. While it sports the Jantzen and the Bates labels, there is no reference to Ballerino. I think it is safe to say my suit is part of the same collection, seeing the use of black in conjunction with the distinctive print.
In 1946 the two piece bathing suit was relatively new, having been first shown by Carolyn Schnurer in 1931, but taking almost a decade before gaining popular approval.