I went and read Alains matting page and there is only one thing I would disagree with...
DO NOT tape your photo to the back of the mat!!!!
I cannot stress this enough!!!
First reason: If someone has to open the package and lifts the mat, there is always the chance of tearing the photo (or whatever).
Second: If the mat gets damaged and has to be replaced, the image is already in place and the new mat just needs to be put back on. The other way, you have to remove the image from the damaged mat, possibly damaging it and then you still have to remount the image. Waste of time and possibly damaging to the art.
Always mount to the backer board, whatever it may be... rag mat or acid free foam core, or whatever you use.
One other thing that bugs the he** out of me...
Do not tape it all the way across the top of the paper, or all the way around the paper!!!
That is what makes the paper ripple and buckle. You have given it no room for expansion and so it does the only thing it can do, ripple in the middle of the paper, and then I'M supposed to remove the tape and then magically make it flat again.
...and do not use masking tape, duct tape, brown packing tape or even bandaids!!! All of which I have encountered upon opening artists framing jobs.
Whew! I feel MUCH better now.
I can now get back to framing.