Comments about 3M Scotch Photo Mount Spray Adhesive:

Does the job well. I suggest you use this technique for your mounting. Works fine if you're careful.
I found this tip on another forum. Follow the earlier tip above to lay out both photo and mounting board on newspaper to spray and don't touch until tacky dry. Also be careful not to touch the surface of the print with fingers that may have adhesive residue.

"Get a roller (hard rubber roller/brayer used for block printing or a wood veneer roller), a can of 3M adhesive, and wax paper.

Spray the back of the photo and the board with the spray adhesive. Allow it so dry for a few minutes so that it is not very sticky, but tacky. Place your foam board on a hard/firm surface. Place wax paper over the tacky mounting board. Now place your photo on the wax paper and align edges as you wish(or just center it if you will be trimming it later.) Now lift up carefully one edge (a short side) of the photo and pull back the wax paper exposing about an inch or so of the print, and carefully begin to rub it down (recommend using white cotton photo gloves and a cloth) onto the board. Now, you can remove the wax paper. Starting from the glued-down end, gently rub down the print with the cotton cloth to hold the photo in place. Then work your way down the length of the photo/board with the roller until you have adhered the entire photo. Do a small distance at a time and be sure to thoroughly roll the entire width for every short distance you adhere to avoid air pockets. In the event you end up with an air pocket for whatever reason, you can use a needle and puncture either the back (foamcore) to let the air out, or puncture the photo itself.(You're unlikely to see such a tiny hole) Then just roll down the pocket."

(This is the same technique cabinet makers use to apply Formica to counter tops.)
-- Good luck.

Comments about 3M Scotch Photo Mount Spray Adhesive:

***CAUTION - OVERSPRAY WILL RUIN YOUR PRINT***

The technique I use is this:

1. Lay newspaper or some other waste paper out on a work surface.
2. Lay print face down on the newspaper.
3. On second work surface, lay out your mounting board, finished face up. This board MUST be bigger than your desired finished size, PLUS a little play.
4. Spray as directed on the back of your print all the way to the edges.
5. Lift your print (may need second person depending on size), flip, and place on mounting board. Again depending on size, you may want to start with one edge and work by rolling it down into place. For small prints, say smaller than 20" x 20", I just place it down all at once.
6. Using one of those microfiber cloths that you clean eyeglasses with, start in the center of your print and working outwards, apply pressure to the print to make for 100% contact with the mounting board.
7. Cut the mounting board to your desired size.

***CAUTION - once you pick up your print you will likely have residual adhesive on your finger tips. DO NOT TOUCH YOUR PRINTS! The adhesive will mar your print. Use either white gloves or microfiber cloths to handle your prints. This adhesive is NOT water soluble, so just washing your hands WILL NOT be sufficient. Trust me, I've made that mistake.

Comments about 3M Scotch Photo Mount Spray Adhesive:

I ruined a $30 (20x30) print, $5 worth of foam core, and wasted the entire can of spray trying to mount my own print at home. I am not stupid, I am very careful. I am VERY disappointed that this product did not have better instructions. I even looked up tutorials online and could not get anything that would have helped me. Obviously the spray adhesive works like a charm. It WOULD have been perfect had I used the correct technique (which I am still looking for). So moral of the story: this stuff works great, but use caution and make sure you have the right technique. DO NOT THINK YOU CAN EASILY DIY. My guess is that it would be better to spray as your mounting. In other words:1) line up left side of photo with mount and secure in place.2) lift up right side of photo and roll over the secured left side.3) begin spraying photo and mount board covering most of the photo and mount board, except a few inches on the left side (which is secured).4) wait a minute or two for glue to dry before gently rolling photo in place on mount board from left to right.5) once photo is secure with glue, then finish using the same process on the few unglued inches of the left side.if I had to do over again, this is what I would do. But then again, it might not be the right way either.