I do remember my Mom making aprons out of the original flour sack material - with a family of five children, and being a 'bread baker' -- flour was purchased in those very large fabric sacks.  Now, every time I see these prints -- in my minds eye, I can see one of Mom's aprons hanging on a peg by the our kitchen door.  
By the way -- the blue fabric is called:   'Wash Day' !
