Antique style of frame

[Judders]

How do you put together a frame of this style favoured for oil paintings.

[prospero]

That looks like a panel with a raised edge on the inside with a narrower moulding set around it.

That particular example would have been made from plain wood. Cut and joined and the two elements
fixed together an a permanent manner. After that a few coats of gesso and when smooth enough the inner
and outer edges gilded. The inner panel is painted. It also looks as if a dusty wash has been applied.
The inner bevelled liner is made separately and added last.

You can spot this 'closed corner' type of construction by the slightly rounded corners and that no mitre lines are visible.
The thick coat of gesso also tends to blur any sharp edges on the profiles.

I do a lot of these although I don't use trad gesso or leaf gold but the principle is the same.
It's quite a versatile system for making a frame as you can use just a flat piece of timber and latch on mouldings outside and
inside to your taste. You can produce almost endless variations. It's also a good way of making very wide profiles which are very
stable due to their laminated build.

Of course you can achieve the same sort of frame using factory-finished mouldings.
Your choices however are limited to what is available.

And you don't get the same nice blended corners....