How to Crop or Re-Size a Finished Oil Painting

Have you ever wanted to crop a finished painting to adjust the composition?  Maybe move the focal point or decrease the negative space?  I do all the time, even after careful planning.  A post by Robert Genn inspired me to experiment with the portrait of Nick from my last post.  I thought there was too much negative space in the composition.  I'm happier with the cropped "after" version below.  Nicer shapes, I think.

Portrait of Nick (after cropping) 16x12", oil on linen board

Portrait of Nick (before cropping) 20x16", oil on linen

This resizing method works for paintings on stretched canvas, not canvas board.   Here's how I did it...

1. This painting was on stretched linen which I wanted to crop from 20x16" down to 16x12".  The painting was dry to the touch.  I laid it face down on a piece of clean sketch pad newsprint.  (Don't use plastic or wax-coated papers. They may burnish the finish and create shiny spots on the painting.)  
2. I cut the painting from the stretcher bars with a sharp knife, then laid it face up and moved a 16x12" frame above it until I got the composition I wanted.  
3. I poked holes in each corner of the framed image with a tack, then connected the tack holes on the back of the painting with pencil marks to create placement guides.
4. After researching adhesives, I chose gesso (PVC glue sounds too messy).  Gesso creates a secure bond, cleans up easy, it's readily available, and it's archival.  I used Liquitex liquid gesso.  Nothing fancy.  I did a test run with some old canvas.
5. I coated the entire back of the cropped painting with a slather of gesso, then laid a 16x12" board on top.  I flipped the painting over (board-side down), and with a piece of newsprint for protection, gently rubbed the painting from the center out to the edges with a big wad of cloth to eliminate air pockets.  I put another board on top of the burnished painting, added a heavy weight and let it sit overnight.
6. To finish I cut an extra 1" margin around the mounted canvas, then folded that over and glued it to the board back with more gesso.  Finally I covered the raw edges on the back with a nice piece of paper, just a bit smaller than the board.  It looks good.  For a simpler finish, cut the painting with a razor along the board edge. Skip the fold-over.  

Aside from re-sizing, I made other changes to the background and to the portrait itself.  The finishing touch is the gold-leafed frame, which adds the yellow to the basic red/blue/yellow color scheme.  It is done.