I found this on this web site about poplin. (I was curious.)
https://support.spoonflower.com/hc/e...For-My-Project
*** as stated on the website*** (quilting) Cotton Poplin is a fine weave cotton similar to standard men’s shirting material, and prints with somewhat muted, subtle colors.
There is a whole write up on the best use for different fabrics also if your interested. (on the same page)