Hi,
Affinity Designer newbie here, using desktop version on an iMac.
I've opened a couple of the sample Designer files to see how they work and everything looks fairly familiar, or at least intuitive.
One thing that's puzzled me is the fill colour in the background blue in the sample file 'Prison of Arts'. It's a dark blue colour, but has a slight graininess to it, rather like adding noise in Photoshop. A new rectangle, filled with a colour also takes on this graininess.
I quite like the effect, but can't replicate it in a new file - nor can I turn it off in the sample file 'Prison of Arts'. I've explored settings, effects and all sorts, but can't find how to add or turn off the effect - any help gratefully received.
Screenshot at 200% scale attached.