I kind of like the idea of signing on the border of the print and covering it with the mat, but then you and your name remain in obscurity, unless you sign the mat or the back of the mounting board. Some photographers use stamps. Perhaps the use of a stamp would not be as tacky as signing the image. Of course, if there were ways of keeping fiber paper from curling with humidity, one could just hinge prints with acid free tape and sign them on the reverse side of the print. Anyone had any luck with fiber printing papers that don't curl or bulge?