I had a flower painting some months ago that was going reasonably well and then I noticed a weird bumpy texture (I posted about it somewhere but can't find where it - doesn't matter).
I thought it was from my paper towels - that was my best guess because I was using all Geneva and no medium to speak of.
I happened to be reading something about Rembrandt and mention was made of his bumpy textures and how much of it was because of dried bits of paint that accumulate in brushes or even the bottom of paint piles. Another artist was mentioned as well (can't remember the name) and that they used these tiny drying paint dots/blobs in their work. That got me to thinking.
I push the limits of drying times - I have a masterson box for my palette that is like a tuperware seal and I will pretty much use all the paint I can that I squeeze out - then I just add on top if I run out. For that flower painting and a few more since then - I think I had more drying bits of paint mixed in with the fresh. It is incredibly unattractive - I suppose it could work for clothing or desired texture if you can control it.
So, I will be aware of drying paint on my palette. It is at the perfect time where it is almost dry - that is when little paint beads happen.
Just FYI if anyone else happens to find a weird beady texture suddenly.