Your choice of gloss or lustre finish print, mounted, ready to insert into your frame.
Loose prints are fragile. Paper can be torn, stained, creased. It is important to preserve your prints. A mount is the board that will sit directly behind the print, giving it rigidity and keeps larger prints flat for framing.
A window mat, or aperture mount, on top of your print will separate the print from the glass creating a vital mechanical barrier. It will also add to impact of your print by creating a border to isolate the image from the frame itself, which could have otherwise overpowered the print.
Although available in a variety of colours, it is best to stick to subtle colours such as white, cream, ivory. I am also a fan of black mounts which can enhance particular prints.