Paper strips are glued to each rib joint as reinforcement.  This is an easy process.  First cut paper strips of the desired width.

Dry fit a paper strip in place to mark and trim the ends for a good fit.  I like to place a tab or two of tape as alignment so the paper strip remains centered on the rib joint.

 

 Apply the glue of your choice to the lute rib joint first - then align the paper - and apply a layer of glue on top of the paper.

 Smooth the glue and press the paper into the joint to get good contact.

 Finished....

Warning!

Experimental process follows.....
Once I dropped a completed Baroque lute shell before the top was added. The shell cracked and split for half its' length....ouch!
It was obvious that the paper reinforcing strips had little effect on preventing cracks from propagating.
So, as an experiment here is a shell reinforced with woven carbon fiber composite instead of paper.

Because the carbon fabric is woven you can't just cut into strips - it will unravel.
However, it is easy to spray the fabric first with a clear laquer or similar spray that holds the fibers together enough to cut into strips
....but still allows the glue to penetrate throughout the fabric weave.

Even though the fabric has been sprayed to prevent fraying, it is still very flexible.
Just use a straight edge to make the weave straight. Then cut a strip with a sharp knife.

Glue the carbon fiber strips as you would a paper strip.
I did a test joint in this manner with two small pieces of lute ribs. There was no way to tear them apart.

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