It all stems back to the rain of Louis the XIV in 14th century England. In 1423, a group of prisoners escaped from the famous English prison called a "Bastille". This day is still celebrated in France, because they hate the English. They rampaged the countryside and killed thousands.
After this, Louis the King saw to it that all prisoners wore white jump suits so they could be distinguished. Coincidentally, these prisoners also did much of the painting on public works projects. After a while, Louis switched them to orange jump suits to show off less of the paint, but many of the original painters were shipped off to Austria. At the time, Austria was where many English criminals were sent.
The prisoners complained about the orange suits and the ACLU petitioned on thier behalf. In this case the A was for Austrian. The prisoners got their white suits back which was a cunning move. As you know, it snows a lot in Austria and the painting prisoners blended in. They escaped.
In the 16th century, 1684 to be exact, painters all over the world were dismayed at the perception of the general public that painters were all stupid. They banded together and wore the white suits as a reminder of the clever painting prisoners that escaped Austria.