If you're talking about the military,that was the time period of the Kilmarnock bonnet (hummel). Scroll to the bottom of this page:
http://giftshop.scottishtartans.org/bonnets.htm

Civilian bonnets were by-and-large knitted items - what we today call a "tam o' shanter" - and dark blue was the most popular color, though natural shades of grey and brown were not unknown. Today's "balmoral" is a later development....