Bit obtuse but imagine a door into a house - opening into the house. The external face of the door is painted one colour and the inner face a different colour...but...

..what about the inside edge of the door on the hinge side..outside or inside colour?

..the edge that opens into the room?

.. the inside of the door frame on the internal side of the shutting strip?

Whichever way I look at it I get confused !  Is there a standard approach?

If i am ever asked to paint an external door, it is always as follows.(inward opening door:)

Face and hinge side ..External colour
Rear and lock side .. Internal colour
Frame External, to edge of stop bead(where it meets face of door) External colour:

Frame internal from rear edge of stop bead: (where door butts up to)Internal colour:

top and bottom edges of door, any colour you like as you wont see them BUT..MAKE SURE THEY ARE PAINTED, as this is where most warping occurs from!