Im thinking of making a new front door & frame in douglas fir, but have read that douglas fir does not take paint very well, has anyone else found this to be an issue.
Put some into a boat's deck 2 years ago, it took International non slip deck paint with no problem. (I know that's not what you'd put on a front door , but Int deck paint keys in the same as Int gloss).
It takes paint well, very well! You can shellac the knots or drill them out and plug them. Careful sanding edges as it has a tendency to splinter and they are sharp and long.