Matching plaster texture
 

I have a home built in 1950. I replaced a large fixed window (6'x8') with a smaller (4'x8') operable window. Under the new window is a new smooth GWB wall. Now I need to match the original swirling plaster pattern. It is a smooth finish with many coats of paint over it. There are places where they may have pressed a rag or cloth into it. Two photos are attached. Any suggestions on how to create this texture?

David

you might want to try the drywall forum, or search for a plaster forum.

The bottom pic looks like it might be a variation of the old time coffee can method. They used to use the bottom of cans to get the circles. Usually on ceilings.

That looks like a can, some more manipulation and burnishing (sanding). But, I'm not a plaster man.

The top picture....I have no idea.

Try a wet towl or rag that should do it with a coffee can