We heard from a client who wanted to frame their ketubah just like the one pictured. Here's how we replied.
The total frame width is about 18 x 24 inches. The sizes can be modified depending on which Ketubah was ordered.
The mat opening is about 11 x 17 inches. (This means that most of the margins of the ketubah are covered by the mat. The framer left about 1/2 inch margins around the papercut design, maybe a bit less.)
Frame depth is 1 inch.
We used double mat technique, if I recall correctly; there is a strip of silver, a couple of mm wide, next to the white mat. Or it could be a special mat. Not sure.
Not sure about angle or thickness of the mat. Probably 45 degrees? We didn't do anything unusual here.
Color of the frame and mat you should be able to discern from the photos. The mat is just a slightly lighter and whiter than the ketubah paper. The backing board is a bit darker, but still a relatively pale speckled beige / gray. The frame is what Israelis call "milky" natural wood. (For what it's worth, these were all among the less expensive choices at my framer's, as I had to frame 30 pieces for a show and had a budget to stick to! So you shouldn't have to break the bank here to get the same basic effect.)
Two layers of regular glass (reflective.) One atop the mat and artwork, and then a layer below that. Behind that are spacers, and then the backing board.
Below are some detailed snapshots that are helpful as well.
^ Final result!