The true Purdue colors are black and what is sometimes called old gold. Tee shirts are oftem imprinted with metallic paint gold on black cloth. This is impractical, however, for a lot of logoed stuff. So what the manufacturers do is come up with a cloth colored as close as possible to a metallic gold, but its cloth. The gold color ends up looking a little different depending on howthe manufacturer did this, with some using almost a pure yellow. Often it ends up being something of a very subdued dusty or somewhat "discolored" yellow-like color. In looking at the swim briefs the Purdue swimmers are wearing, I would say this is pretty much what happened. What you see as yellow is not a bright yellow, but a dusty goldish, yellowish color.
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