The problem is likely the paint. My wife bought Clark+Kensington for the walls and Royal Interiors for trim (both by Ace Hardware, semi-gloss). Both, but particularly the Royal Interiors, show very heavy brush marks using Purdy brushes. I have done a ton of painting and normally do not have this problem. Next time I will buy better paint. For this time, does anyone have an opinion about adding Floetrol to smooth out the paint? Any other additives or alternatives? Thanks.