Float mount your work with a 50mm reveal in a natural wood frame so the work is floating above the backing board and behind the glazing.
Mount
Float mount the artwork on archival foam core so all the edges are visible.
Margin
Leave a 50mm reveal (visible backing) around all sides. Do not mat over the artwork.
Spacer
Use a spacer so glazing does not touch the artwork.
Raised
Lift the artwork 2-5mm off the backing to create a shadow gap.
Glazing
Use glass or acrylic. If budget allows, go for anti-reflective and UV protection.
Frame
Natural wood (walnut or oak) or white, matte finish, square profile.