The term blue collar worker is not as common as it once was. There is a good reason for this. There is rarely any real blue collar work, in the traditional sense, left. The term comes from the turn of the century and throughout the twentieth. Blue Collar referred to manual and manufacturing work, it was a nod to the hard wearing blue shirts and boiler suits that factory workers would wear. On the other side was the white collar worker. This was someone in an office or finance role. At the time this indicated better pay and social standing. Regardless of your social position a decent set of Farah Shirts (originally developed for the US Army and workwear) bridges the gap.
The assumption that we make is that if it’s a blue collar role then there is a lack of care in the appearance. However this is, and never was, the case. The working man still liked their clothes to fit and look good. Even now the traditional blue collar jobs like a Plumber or electrician require a certain standard of dress as they are in the service sector.
The work shirt is now something of a fashion item. It is thicker than a dress shirt as it is supposed to take more abuse. It is usually made of thicker cotton. It can be any colour.