Black flags on a ground of one colour
4 of the 254 flags in the world are painted in black and were measured on a ground of one colour.
One box different
The same two questions, answered another way.
- Red flags on a ground of one colour 36
- White flags on a ground of one colour 35
- Blue flags on a ground of one colour 31
- Black flags with horizontal bands 29
- Yellow flags on a ground of one colour 10
- Black flags with a triangle at the pole 10
- Green flags on a ground of one colour 9
- Black flags with a diagonal division 4
- Black flags with a disc 2
- Black flags with vertical bands 2
- Orange flags on a ground of one colour 2
- Grey flags on a ground of one colour 1
How a flag gets onto this list
Both halves are taken off the picture rather than from anybody's description of it. The shades beside each flag are what it is really painted in, and they are why it is filed under black.
The shape is the second half: The fly edge and the foot are one colour, and the same one — whatever else is drawn on top of it. That is a measurement of a drawing, so if one of these looks wrong to you, it is that sentence you are disagreeing with — and the flag is right there to argue with.
Open the finder to add what was on it as well.