I love a good dart tip; I came across this one in 'Home Journal' (1954).
Fifties seamstresses were advised to use 'brown paper to press out smooth darts.' Admittedly, I haven't actually used brown paper, I didn't have any to hand, instead I just whipped some regular paper out of my printer.
Below I'm using paper to press a cotton linen mix. Despite pressing hard on a very high temperature, there were no telltale marks coming through on the right side. This also worked well on seams.
The most useful application is when you have those tiny, fiddly shoulder darts. Using paper allowed me to get the iron right over them without worrying that I'd be left with unsightly marks.
These pictures are actually of my final summer dress project, I'll be posting on the completed summer dresses next week.