And with a tropical dial, something sincerely has gone wrong: around the middle of the last century, Rolex primed its dials with a finish that was supposed to protect the watches from sun damage. Bizarrely, it had the exact opposite effect: after years of exposure to the sun, that chemical reacts in a way that discolors the dial. Some Omega watches made during this same period are similarly susceptible to sunlight. The discoloration has the same effect on an Omega’s value, too: In 2015, A Blog to Watch found that the selling prices of Omega Speedmaster Professionals with tropical dials were 334 percent higher than those with plain black ones… More here.
Most of you must think that watch people are bonkers.