Both papers are natural white, cold press, 140 lb (300 gsm) and acid free.
The only difference is the price, as the Windpower is slightly more expensive! A Strathmore 400 Series Watercolor pad, size 18"x24", has a list price of $32.39, whereas a Strathmore Windpower Watercolor pad, same size, has a list price of $37.59, a difference of $5.20. For the smaller sizes, 10"x15" and 9"x12", the difference is less, around $1.64 and $1.24 respectively.
My only comment is that I find the naming a bit confusing and would have preferred the name "Strathmore 400 Series Windpower Watercolor" instead of only "Windpower Watercolor". As a matter of fact, in the Strathmore Dry and Wet Paper Media Guide, the Windpower paper is listed as "400 Windpower Watercolor"!
When I compared the two pads, the paper color, thickness, and texture did indeed match, although the paper in my particular Windpower pad had a slightly less pronounced texture (see picture).
|Comparing Strathmore 400 Series Watercolor (left) and Windpower Watercolor paper (right)|
© 2017 Anna C./See. Be. Draw.