Also, brown and yellow used to be much easier and cheaper shades of paint to make vs whites, blues, or reds (depending on the material to be painted). For exam

Also, brown and yellow used to be much easier and cheaper shades of paint to make vs whites, blues, or reds (depending on the material to be painted). For example, stop signs in the US, while always intended to be red, were originally painted yellow, because there wasn't a red paint cheap or durable enough at the time the traffic standards were developed. As technology caught up and new paints/dyes developed, the yellow signs were replaced with red ones.