Painting the Town

Painting the Town is a side quest in Fallout 4.

Detailed walkthrough
Talk to Abbot at The Wall in the NW part of Diamond City against the green wall with the scoreboard. He will ask you to retrieve a can of paint from Hardware Town. Passing a speech check can get Abbot to pay for the paint up front or give you more caps.

It is not necessary to go to Hardware Town if you already have paint in your inventory. You may also already have the green paint if a radiant quest from the Minutemen lead you to Hardware Town and you mixed green paint.

Exit Diamond City and head west to find Hardware Town. Approaching the store, a settler, seemingly in distress, will shout and ask the Sole Survivor for help. Follow them inside where a group of raiders will be waiting in ambush. Once the raiders have been killed, cans of yellow and blue paint can be collected around the warehouse. At the far back of the storage hall, there is a paint mixer which can be used to mix green paint using yellow and blue paint. Various ammo, loot and valuables can be found in machines and locked chests around the warehouse. There is an issue of Picket Fences upstairs in the main office, on the desk.

Return to Diamond City and use paint on The Wall. Painting the wall blue or yellow will result in a reward of 100 caps from Abbot. Painting the wall green will result in a reward of 200 caps.

Bugs
When you get the miscellaneous objective to "See Abbot at the wall" to initiate the quest you sometimes will not be able to talk to him if you cleared Hardware Town of raiders prior to speaking with him. He will just speak his "I'm busy!" lines. If the Green Paint quest item is in your inventory, it can be dropped before speaking with Abbot to enable the dialogue for the quest, though the quest notification will not pop up when started or completed when the Green Paint is picked up again.