I read this sentence:
This covering up of pipes is all a mistake, they should be exposed everywhere, if necessary painted well and handsomely.
It uses a use of "if necessary" I have never seen before. I searched it up, but found no results. Don't we usually use "if necessary" by itself? I don't know how a past participle can be used after "if necessary".
I think the full version of the phrase should be something like
if (it is) necessary (to be) painted.
But is it a common usage? Is it grammatical? It was written in 19th century, so I don't know if this usage is still used.
The book is called The Devil In The White City, and it is said by Peter Chardon Brooks III in a letter (a real letter -- the book is non fiction).