This one is going to be a real longshot, I fear. I can really remember only one scene from the film or tv special, and not sure of the context of it. Anyway, here we go.
The film is some sort of children's movie with elements of fantasy. Might be a musical or a comedy in nature. I do seem to remember it being fairly light fare in any case. The part I remember best is that there is an adult male character who has a somewhat magical bucket of paint. As a kid, I was certain that the part was played by Dick Van Dyke. My first thought was either Mary Poppins or Chitty Chitty Bang Bang. After doing some googling though, I don't think it's from either of them, and nothing else on his IMDB entry jumps out at me. So, it may not be Van Dyke in the part.
The scene in question involves several children and the adult male character being held somewhere. It might be the local jail, or it might be a reform school for the kids. In any case, the pail of magic paint saves the day. The man paints a door on the wall, and they are able to open it like a real door and make their escape. IIRC, there were a couple of other times in the film when the man was able to paint something magical and useful in the story.
I saw this film or show on tv in the 1970s on "regular" tv (i.e. it wasn't a cable or pay channel thing). Pretty sure it was a weekend afternoon movie presentation. It was definitely in color, and probably came out in the 1960s or 70s. Might have been set in England. Unsure of the period setting of the film (modern, 19th century, etc.)
That's all I've got for this one. Truly sorry to be so vague, but I simply cannot recall anything else about the film.